Contrast medium administration with a body surface area protocol in step-and-shoot coronary computed tomography angiography with dual-source scanners
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ABSTRACT:
SUBMITTER: Jin L
PROVIDER: S-EPMC7541528 | biostudies-literature | 2020 Jan
REPOSITORIES: biostudies-literature
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Project description:To determine whether body weight and concentration dependent contrast medium (CM) injection protocols can improve patient to patient CT value uniformity more than the conventional injection protocols with fixed injection parameters in coronary CT angiography (CCTA), one hundred and sixty patients who underwent CCTA were prospectively randomized into two groups. Group A (n = 80) used individualized-protocol with adjusted injection rate based on patient weight and contrast medium concentration to obtain constant iodine load of 280 mgI/kg while group B (n = 80) followed the conventional contrast injection protocol with total injection volume of 80ml and constant injection rate of 5.5ml/s. For both groups, patients were further divided into four subgroups with different CM concentrations: A1, B1 (300 mg I/ml); A2, B2 (320 mg I/ml); A3, B3 (350 mg I/ml) and A4 and B4 (370 mg I/ml). For each patient, the CT values of the ascending aorta, left ventricle and coronary arteries were measured. One-way analysis of variance was used to compare CT values among subgroups. Among the subgroups of A, sufficient attenuation of greater than 300HU was obtained in all target vessels with no difference among them. Among the subgroups of B, the CT values had significant difference in left ventricle, left circumflex branch, proximal and distal segment of the right coronary artery (all p < 0.05), and the attenuation with 300 mg I/ml CM concentration was significantly lower than that with 370 mg I/ml. Compared with group B, group A used less volume (62.83 ml vs. 80.00 ml, P<0.001) and lower rate (5.21 ml/s vs. 5.50 ml/s, P<0.001) of CM. Compared with the conventional contrast medium injection protocol with fixed volume and injection rate, the individualized-protocol based on patient weight and contrast concentration provides overall contrast dose reduction and achieves more homogenous attenuation among different coronary vessels and patients.
| S-EPMC4500390 | biostudies-literature
Project description:Ammonium nutrition often represents an important growth-limiting stress in plants. Some of the symptoms that plants present under ammonium nutrition have been associated with pH deregulation, in fact external medium pH control is known to improve plants ammonium tolerance. However, the way plant cell metabolism adjusts to these changes is not completely understood. Thus, in this work we focused on how Arabidopsis thaliana shoot and root respond to different nutritional regimes by varying the nitrogen source ([Formula: see text] and [Formula: see text]), concentration (2 and 10 mM) and pH of the external medium (5.7 and 6.7) to gain a deeper understanding of cell metabolic adaptation upon altering these environmental factors. The results obtained evidence changes in the response of ammonium assimilation machinery and of the anaplerotic enzymes associated to Tricarboxylic Acids (TCA) cycle in function of the plant organ, the nitrogen source and the degree of ammonium stress. A greater stress severity at pH 5.7 was related to [Formula: see text] accumulation; this could not be circumvented in spite of the stimulation of glutamine synthetase, glutamate dehydrogenase, and TCA cycle anaplerotic enzymes. Moreover, this study suggests specific functions for different gln and gdh isoforms based on the nutritional regime. Overall, [Formula: see text] accumulation triggering ammonium stress appears to bear no relation to nitrogen assimilation impairment.
| S-EPMC4734181 | biostudies-literature
Project description:Accurate pulmonary artery (PA) imaging is necessary for management of patients with complex congenital heart disease (CHD). The ability of newer imaging modalities such as 3D rotational angiography (3DRA) or phase-contrast magnetic resonance angiography (PC-MRA) to measure PA diameters has not been compared to established angiography techniques. Measurements of PA diameters (including PA stenosis and PA stents) from 3DRA and non-contrast-enhanced PC-MRA were compared to 2D catheter angiography (CA) and multi-slice computed tomography (MSCT) in a swine CHD model (n?=?18). For all PA segments 3DRA had excellent agreement with CA and MSCT (ICC?=?0.94[0.91–0.95] and 0.92[0.89–0.94]). 3DRA PA stenosis measures were similar to CA and MSCT and 3DRA was on average within 5% of 10.8?±?1.3 mm PA stent diameters from CA and MSCT. For compliant PA segments, 3DRA was on average 3–12% less than CA (p?<?0.05) and MSCT (p?<?0.01) for 6–14 mm vessels. PC-MRA could not reliably visualize stents and distal PA vessels and only identified 34% of all assigned measurement sites. For measured PA segments, PC-MRA had good agreement to CA and MSCT (ICC?=?0.87[0.77–0.92] and 0.83[0.72–0.90]) but PC-MRA overestimated stenosis diameters and underestimated compliant PA diameters. Excellent CA-MSCT PA diameter agreement (ICC?=?0.95[0.93–0.96]) confirmed previous data in CHD patients. There was little bias in PA measurements between 3DRA, CA and MSCT in stenotic and stented PAs but 3DRA underestimates measurements of compliant PA regions. Accurate PC-MRA imaging was limited to unstented proximal PA anatomy. Electronic supplementary material The online version of this article (10.1007/s10554-020-02043-9) contains supplementary material, which is available to authorized users.
| S-EPMC7545377 | biostudies-literature
Project description:One of the main drawbacks associated with Dual Energy Computed Tomography Angiography (DECTA) is the risk of developing contrast medium-induced nephropathy (CIN). The aim of the present study was firstly, to design an optimal CT imaging protocol by determining the feasibility of using a reduced contrast medium volume in peripheral arterial DECTA, and secondly, to compare the results with those obtained from using routine contrast medium volume.Thirty four patients underwent DECTA for the diagnosis of peripheral arterial disease. They were randomly divided into two groups: Group 1 (routine contrast volume group) with n = 17, injection rate 4-5 ml/s, and 1.5 ml/kg of contrast medium, and Group 2 ((low contrast volume group), with n = 17, injection rate 4-5ml/s, and contrast medium volume 0.75 ml/kg. A fast kilovoltage-switching 64-slice CT scanner in the dual-energy mode was employed for the study. A total of 6 datasets of monochromatic images at 50, 55, 60, 65, 70 and 75 keV levels were reconstructed with adaptive statistical iterative reconstruction (ASIR) at 50%. A 4-point scale was the tool for qualitative analysis of results. The two groups were compared and assessed quantitatively for image quality on the basis of signal-to-noise ratio (SNR) and contrast-to-noise-ratio (CNR). Radiation and contrast medium doses were also compared.The overall mean CT attenuation and mean noise for all lower extremity body parts was significantly lower for the low volume contrast group (p<0.001), and varied significantly between groups (p = 0.001), body parts (p<0.001) and keVs (p<0.001). The interaction between group body parts was significant with CT attenuation and CNR (p = 0.002 and 0.003 respectively), and marginally significant with SNR (p = 0.047), with minimal changes noticed between the two groups. Group 2 (low contrast volume group) displayed the lowest image noise between 65 and 70 keV, recorded the highest SNR and CNR at 65 keV, and produced significantly lower results with respect to contrast medium volume and duration of contrast injection (p<0.001). The effect of radiation dose was not statistically significant between the two groups.DECTA images created at 65 keV and 50% ASIR with low contrast medium volume protocol, yielded results that were comparable to routine contrast medium volume, with acceptable diagnostic images produced during the evaluation of peripheral arteries.
| S-EPMC4587806 | biostudies-literature
Project description:BackgroundMicrovascular dysfunction (MVD) is a potential cause of chest pain in younger individuals. The authors hypothesized that nonelderly patients referred for computed tomographic angiography (CTA) but without significant stenosis would have a high prevalence of MVD by myocardial contrast echocardiography (MCE). Secondary aims were to test whether the presence of nonobstructive coronary artery disease (CAD) or reduced brachial flow-mediated dilation (FMD) predicted MVD.MethodsSubjects ≤60 years of age undergoing CTA were recruited if they had either no evidence of coronary plaque or evidence of mild CAD (<50% stenosis) and at least one high-risk plaque feature. Subjects underwent quantitative perfusion imaging using MCE at rest and during regadenoson vasodilator stress. MVD was defined as global or segmental delay of microvascular refill (≥2 sec) during regadenoson. FMD of the brachial artery was also performed.ResultsOf the 29 patients in whom MCE could be performed, 12 (41%) had MVD. These subjects, compared with those with normal microvascular function, had lower hyperemic perfusion (mean, 236 ± 68 vs 354 ± 161 intensity units/sec; P = .02) and microvascular flux rate (mean, 1.6 ± 0.4 vs 2.5 ± 0.9 sec-1; P = .002) on quantitative MCE. The degree of FMD was not significantly different in those with or without MVD (mean, 11 ± 4% vs 9 ± 4%; P = .32), and there was a poor correlation between results on stress MCE and FMD. Only eight of the 29 subjects were classified as having nonobstructive CAD. There were no groupwise differences in the prevalence of MVD function in those with versus without CAD (43% vs 38% for negative and positive findings on CTA, respectively, P = .79).ConclusionsMVD is a common finding in the nonelderly population referred for CTA for evaluation of possible CAD but without obstructive stenosis. Neither the presence of noncritical atherosclerotic disease nor abnormal FMD increases the likelihood for detecting MVD in this population.
| S-EPMC6527356 | biostudies-literature
Project description:Background and purposeRadiomics analysis extracts quantitative data (features) from medical images. These features could potentially reflect biological characteristics and act as imaging biomarkers within precision medicine. However, there is a lack of cross-comparison and validation of radiomics outputs which is paramount for clinical implementation. In this study, we compared radiomics outputs across two computed tomography (CT)-based preclinical scanners.Materials and methodsCone beam CT (CBCT) and µCT scans were acquired using different preclinical CT imaging platforms. The reproducibility of radiomics features on each scanner was assessed using a phantom across imaging energies (40 & 60 kVp) and segmentation volumes (44-238 mm3). Retrospective mouse scans were used to compare feature reliability across varying tissue densities (lung, heart, bone), scanners and after voxel size harmonisation. Reliable features had an intraclass correlation coefficient (ICC) > 0.8.ResultsFirst order and GLCM features were the most reliable on both scanners across different volumes. There was an inverse relationship between tissue density and feature reliability, with the highest number of features in lung (CBCT=580, µCT=734) and lowest in bone (CBCT=110, µCT=560). Comparable features for lung and heart tissues increased when voxel sizes were harmonised. We have identified tissue-specific preclinical radiomics signatures in mice for the lung (133), heart (35), and bone (15).ConclusionsPreclinical CBCT and µCT scans can be used for radiomics analysis to support the development of meaningful radiomics signatures. This study demonstrates the importance of standardisation and emphasises the need for multi-centre studies.
| S-EPMC11328005 | biostudies-literature
Project description:The objective of this study is to evaluate the safety and quality of computed tomographic angiography of the thoracic aorta (CTA-TA) exams performed using intraosseous needle intravenous access (ION-IVA) for contrast media injection (CMI).All CTA-TA exams at the study institution performed between 1/1/2013 and 8/14/2015 were reviewed retrospectively to identify those exams which had been performed using ION-IVA (ION-exams). ION-exams were then analyzed to determine aortic attenuation and contrast-to-noise ratio (CNR). Linear regression was used to determine how injection rate and other variables affected image quality for ION-exams. Patient electronic medical records were reviewed to identify any adverse events related to CTA-TA or ION-IVA.17 (?0.2%) of 7401 exams were ION-exams. ION-exam CMI rates varied between 2.5 and 4 ml/s. Mean attenuation was 312 HU (SD 88 HU) and mean CNR was 25 (SD 9.9). A strong positive linear association between attenuation and injection rate was found. No immediate or delayed complications related to the ION-exams, or intraosseous needle use in general, occurred.For CTA-TA, ION-IVA appears to be a safe and effective route for CMI at rates up to 4 ml/s.
| S-EPMC5784769 | biostudies-literature
Project description:BACKGROUND:Statins are shown effective by some studies in preventing contrast-induced nephropathy (CIN). We evaluated the effectiveness of atorvastatin in the prevention of CIN in computed tomography angiography (CTA) candidates. METHODS:This study was conducted on patients referring for elective CTA with normal renal function. Patients received atorvastatin (80 mg/day) or placebo from 24 h before to 48 h after administration of the contrast material. Serum creatinine was measured before and 48 h after contrast material injection. CIN was defined as an increase in serum creatinine level of ? 0.5 mg/dl or ? 25% of the baseline creatinine. RESULTS:A total of 236 patients completed the study; 115 atorvastatin, 121 placebo, mean age = 58.40 ± 9.80 year, 68.6% male. Serum creatinine increased after contrast material injection in both the atorvastatin (1.00 ± 0.16-1.02 ± 0.15 mg/dl, P = 0.017) and placebo groups (1.03 ± 0.17-1.08 ± 0.18 mg/dl, P < 0.001). Controlling for age, gender, comorbidities, drug history, and baseline serum creatinine level, patients who received atorvastatin experienced less increase in serum creatinine after contrast material injection (beta = 0.127, P = 0.034). However, there was no difference between the atorvastatin and placebo groups in the incidence of CIN (4.3 vs. 5.0%, P = 0.535). CONCLUSION:In patients undergoing CTA, a short-term treatment with high dose atorvastatin is effective in preventing contrast-induced renal dysfunction, in terms of less increase in serum creatinine level after contrast material injection. Further trials including larger sample of patients and longer follow-ups are warranted.
| S-EPMC4251479 | biostudies-literature
Project description:Several methods of imaging the Eustachian tube have been tested in the last century, although neither has led to an established method. The introduction of balloon Eustachian tuboplasty (BET) has revived the request for Eustachian tube (ET) visualization in patients with chronic Eustachian tube dysfunction. Many institutions perform preoperative computed tomography (CT) scans of the temporal bone and epipharynx before BET. Purpose We hypothesize that the injection of a contrast medium into the tympanic cavity is safe and feasible and can evolve the CT scan by visualizing the ET lumen and, potentially, the level of obstruction. This study is the initial feasibility study for such a human application. Material and Methods Ten minutes before a CT scan, diluted iodixanol was injected into the middle ear in 18 patients planned for BET due to otitis media with effusion. Five patients with Meniere's disease were controls. Any immediate or delayed adverse events were recorded. Masking of adjacent bony structures in the middle ear on the CT images was evaluated and the most caudally visible contrast medium between the middle ear and epipharynx recorded. Results There were no serious adverse events. One patient reported transitory vertigo. The contrast medium did not mask middle ear structures, apart from the tympanic membrane. The level of contrast medium passage could be assessed. Conclusion Visualizing the ET lumen in humans using intratympanic contrast medium is feasible and safe and does not obscure other valuable image information in a preoperative CT scan.
| S-EPMC6977099 | biostudies-literature
Project description:The objective of the present study was to evaluate image quality and radiation dosage using a low-dose prospectively electrocardiogram (ECG)-gated computed tomography (CT) protocol for dual-source angiography in children with complex congenital heart disease. A total of 206 patients with complex congenital heart disease were equally assigned into two groups at random. The children in group A underwent low-dose retrospective ECG-gated CT scanning with an ECG-pulsing technique, and group B underwent prospective ECG-gated scanning with an ECG-pulsing technique. Radiation dose volume computed tomography dose index (CTDI vol), dose length product (DLP) and effective dose (ED) were recorded after scanning. Raw data were transferred to workstations for post-processing, diagnosis, grading, comparison with intra-operation findings or cardiac catheterisation, and the coincidence, false negative rate and misdiagnosis rates of groups A and B, respectively, were subsequently recorded. The results of the present study indicated that the height, age and weight of the children in the two groups exhibited no significant differences. The image quality of group A was graded as 3.94±0.08, whereas the grade for the image quality in group B was 4.05±0.08; no significant difference was detected. The coincidence rates of groups A and B were 89.37 and 88.48%, respectively; the false negative rates of groups A and B were 9.66 and 10.60%, respectively; the misdiagnosis rates of groups A and B were 0.97 and 0.92%. No significant differences between the two groups were detected. The CTDI value of group A was 3.24±1.62 mGy, the DLP value was 47.53±33.28 mGy·cm2, the ED value was 0.93±0.42 mSv. By contrast, the CTDI value of group B was 2.27±0.94 mGy, the DLP value was (27.03±17.64) mGy·cm2, and the ED value was 0.53±0.23 mSv. Significant differences were detected between the two groups (CTDI t=5.287, P<0.05; DLP t=5.523, P<0.05; ED t=8.497, P<0.05), and the radiation dose of group B was markedly decreased, compared with group A. In conclusion, the present study demonstrated that prospectively ECG-gated scanning of dual-source CT is an effective method of examination for dose reduction in children with congenital heart disease without impairment of image quality, which suggests that this protocol may be suitable for future application and dissemination.
| S-EPMC5526138 | biostudies-other