Low Contrast Agent Research Articles

Effect of automatic spectral imaging mode selection and adaptive statistical iterative reconstruction at abdominal CT with low contrast agent dose

Objective To investigate the image quality and radiation dose of automatic spectral imaging mode selection and adaptive statistical iterative reconstruction (ASIR) at abdominal CT with low contrast agent dose. Methods One hundred cases with the arterial-phase (AP) and portal venous phase (PVP) contrast-enhanced abdominal CT scanning were analyzed prospectively. Patients were randomly assigned to the study group and control group (n=50 each). In the study group, automatic spectral imaging mode selection and contrast agent dose of 300 mg/kg were used and spectral monochromatic images(40 to 60 keV) were reconstructed using either filtered back-projection (FBP) (group A) or ASIR (group B). In the control group, the fixed tube potential of 120 kVp and contrast agent dose of 450 mg/kg were used with images reconstructed using FBP (group C). Quantitative parameters (image noise and contrast-to-noise ratio of the liver, pancreas, aorta and portal vein) and qualitative visual parameters (overall image quality as graded on a 5-point scale) were compared among the groups by using One-way ANOVA or Kruskal-Wallis H test. Two sample t tests were used compare the radiation dose difference. Results There had no significant difference in CTDIvol[both (12±5) mGy] and DLP[(364±142) mGy·cm versus (377±131) mGy·cm] between the study group and control group(t= -0.408 and -0.428,P>0.05). During the AP and PVP, at the energy level of 40 keV, group B showed higher CNRs than group A and group C, lower image noise[(29±6) HU in AP, (24±6) HU in PVP] than group A[(43±11) HU, (44±10) HU] but higher image noise than group C[(18± 4) HU, (18±4) HU], lower overall image quality scores[(3.0±0.2) point, (2.9±0.3) point] than group C[(3.6± 0.4) point , (3.6±0.5) point] but similar scores to group A[(2.9±0.4) point,(2.8±0.4)point]. At the energy level of 50 keV, group B showed higher CNRs than group A but higher than or similar CNRs to group C, lower image noise[(20±5) HU, (20±4) HU] than group A[(31±8) HU, (31±7) HU] but similar image noise to group C, higher overall image quality scores[(3.6±0.4) point, (3.5±0.4) point]than group A[(3.3±0.3) point,(3.3±0.3) point] but similar scores to group C. At the energy level of 60 keV, group B showed lower image noise[(14±4) HU, (14±3) HU], higher CNRs and overall image quality scores[(3.9±0.4) point,(3.9±0.3) point] than group A[(19±5) and (20±5)HU in image noise, (3.7±0.4) and (3.7±0.3) point in overall image quality scores ]and group C. Except for monochromatic images at 40 keV, the overall image quality scores in group B were all greater than 3 point and met the clinical diagnostic level. Conclusions The radiation dose of CT spectral imaging and conventional 120 kVp CT scan is equivalent with the use of automatic spectral imaging mode selection. By combining ASIR technique, monochromatic images at 50 and 60 keV can improve CNR and reduce contrast agent dose while maintain or improve overall image quality. Key words: Tomography,X-ray computed; Comparative study; Radiation dosage; Image quality

Coronary Computed Tomographic Angiography at Low Concentration of Contrast Agent and Low Tube Voltage in Patients with Obesity:: A Feasibility Study

Using lower tube voltage can reduce the exposure to radiation and the dose of contrast agent. However, lower tube voltage is often linked to more noise and poor image quality, which create a need for more effective technology to resolve this problem. To explore the feasibility of coronary computed tomographic angiography (CCTA) in patients with obesity at low tube voltage (100 kV) and low contrast agent concentration (270 mg/mL) using iterative reconstruction. A total of 48 patients with body mass index greater than 30 kg/m(2) were included and randomly divided into two groups. Group A received a traditional protocol (iopromide 370 mg/mL + 120 kV); group B received a protocol with low tube voltage (100 kV), low contrast agent concentration (270 mg/mL), and iterative reconstruction. The effective dose (ED), average attenuation values, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), the figure of merit (FOM), image quality scores, and the total iodine intake were compared. No significant differences in average CT attenuations, SNR, CNR, and subjective scores were noticed between the two groups (P > 0.05), whereas the FOM of group B was significantly higher than that of group A. Effective radiation dose, total iodine, and iodine injection rate in group B were lower than those of group A (P <0.01). In patients with obesity, isotonic contrast agent with low iodine concentration and low-dose CCTA were feasible. Substantial reduction in radiation dose and the iodine intake could be achieved without compromising the image quality.

Low-Contrast and Low-Radiation Dose Protocol in Cardiac Computed Tomography: Usefulness of Low Tube Voltage and Knowledge-Based Iterative Model Reconstruction Algorithm.

This study aimed to evaluate the feasibility of a low contrast, low-radiation dose protocol of 80-peak kilovoltage (kVp) with prospective electrocardiography-gated cardiac computed tomography (CT) using knowledge-based iterative model reconstruction (IMR). Thirty patients underwent an 80-kVp prospective electrocardiography-gated cardiac CT with low-contrast agent (222-mg iodine per kilogram of body weight) dose. We also enrolled 30 consecutive patients who were scanned with a 120-kVp cardiac CT with filtered back projection using the standard contrast agent dose (370-mg iodine per kilogram of body weight) as a historical control group. We evaluated the radiation dose for the 2 groups. The 80-kVp images were reconstructed with filtered back projection (protocol A), hybrid iterative reconstruction (HIR, protocol B), and IMR (protocol C). We compared CT numbers, image noise, and contrast-to-noise ratio among 120-kVp protocol, protocol A, protocol B, and protocol C. In addition, we compared the noise reduction rate between HIR and IMR. Two independent readers compared image contrast, image noise, image sharpness, unfamiliar image texture, and overall image quality among the 4 protocols. The estimated effective dose (ED) of the 80-kVp protocol was 74% lower than that of the 120-kVp protocol (1.4 vs 5.4 mSv). The contrast-to-noise ratio of protocol C was significantly higher than that of protocol A. The noise reduction rate of IMR was significantly higher than that of HIR (P < 0.01). There was no significant difference in almost all qualitative image quality between 120-kVp protocol and protocol C except for image contrast. A 80-kVp protocol with IMR yields higher image quality with 74% decreased radiation dose and 40% decreased contrast agent dose as compared with a 120-kVp protocol, while decreasing more image noise compared with the 80-kVp protocol with HIR.

Preliminary study of individualized contrast injection protocols in triple-rule-out computed tomography angiography using a high-pitch dual-source technique

To assess the feasibility of individual contrast injection protocols in triple-rule-out computed tomography examination using a dual-source Flash-chest-pain technique. From April to August 2014, 63 patients with undifferentiated acute chest pain underwent ECG-synchronized dual-spiral chest CT angiography. 31 Patients, who all had low (<65 bpm) and stable heart rate underwent TRO CT angiography in a Flash mode, with an individual triphasic contrast protocol based on weight (350 mgI/ml, A: 0.7 ml/kg, setting 10 s duration time; B: 8 s mixture of the contrast agent and saline at the same rate; C: 6-7 s saline at the same rate). In contrast, the other patients, who had random heart rate, underwent TRO CT angiography in a traditional retrospectively mode with an identical biphasic contrast protocol (350 mgI/ml, A: contrast agent 90 ml, B: saline 40 ml, injection rate 5 ml/s). Quantitative image analysis assessed vessel attenuation of aorta, coronary and pulmonary artery, signal-to-noise ratio (SNR) and contrast-to noise ratio (CNR). Subjective image was assessed on a 5 point scale (1: excellent, 5:non-diagnosis) by two blind observers. The effective dose was calculated from the dose length product (DLP) using a conversion coefficient of 0.017 mSv·mGy(-1)·cm(-1). There was no significant difference of aorta and coronary artery attenuation, noise, SNR, CNR or subjective image quality between both patient groups. Pulmonary artery attenuation was lower in test group than in control group, but it also can meet the diagnostic criteria. Moreover, the mean contrast agent and the effective dose were lower in test group than in control group (72±10) vs (90±0) ml, P<0.01 and (3.0±0.3) vs (18.8±2.7) mSv, P<0.01. As to patients with low and stable heart rate, this individual contrast protocol along with dual-source high-pith technique, is capable of achieving satisfactory image which could meet the diagnostic requirements with lower contrast agent and lower effective dose.

Novel Carbon Nanohybrids As Highly Efficient Magnetic Resonance Imaging Contrast Agents

Gadofullerenes derivatives had been proved to exhibit high relaxivities, even higher than that of commercial Gd-DTPA contrast agents. However, all reported gadofullerene contrast agents were based on the functionalized metallofullerene. In this presentation, we successfully constructed novel water-soluble carbon nanohybrids based on unmodified metallofullerene and graphene oxide, which exhibited high relaxivity and better brightening effect in magnetic resonance (MR) imaging in vivo. Gd@C82 was produced and isolated by the industrial-scale production line of metallofullerenes firstly established in Institute of High Energy Physics, Chinese Academy of Science (CAS). A “secondary spin-electron transfer” relaxation mechanism was proposed to explain how the encaged Gd3+ ions of carbon nanohybrids interact with the surrounding water molecules. This approach opens new opportunities in developing highly efficient and low toxic MRI contrast agent. Figure 1

Urinary kidney injury molecule-1 as an early indicator to predict contrast-induced acute kidney injury in patients with diabetes mellitus undergoing percutaneous coronary intervention.

With the improvement of the skill level of coronary intervention, contrast agents are used more widely. As a result, contrast-induced acute kidney injury (CI-AKI) is currently the third leading cause of hospital-acquired AKI. Traditionally, AKI is defined by measuring an increase of the serum creatinine concentration (Scr). CI-AKI indicates impairment in renal function, which is diagnosed as an elevation in the SCr levels following intravascular injection of the contrast media. However, Scr is an insensitive indicator for detecting CI-AKI. The present study was designed to investigate whether human urinary kidney injury molecule-1 (KIM-1) is an early marker to predict CI-AKI in patients with diabetes mellitus undergoing percutaneous coronary intervention (PCI). The present study includes the general clinical data of 145 patients with diabetes mellitus who underwent PCI between March 1, 2013 and December 31, 2013. A non-ionic, low osmolarity contrast agent was used during the present study. The Scr levels and estimated glomerular filtration rate were measured prior to and within 24 and 48 h after the injection of contrast agents. Urinary samples were collected prior to and within 2, 6, 12, 24 and 48 h after the coronary interventional procedure. Simultaneously, the urinary KIM-1 values were measured using an ELISA kit. CI-AKI was diagnosed as an increase of ≥0.5 mg/dl or ≥25% in Scr concentration over baseline, 24-48 h after the procedure. In total, 19 of 145 (13.1%) patients exhibited CI-AKI. There was a significant difference (P<0.05) between the urinary KIM-1 levels measured 2, 6, 12, 24 and 48 h after the procedure and those prior to the procedure in the CI-AKI group. There was no significant difference between the Scr values measured 24 h after the procedure and those prior to the procedure. Evidently, using KIM-1 values to predict CI-AKI was <24 h earlier compared to using Scr values. The area under the receiver operating characteristic curve of KIM-1 24 h after the procedure was 0.856 and the 95% confidence interval of the corresponding area was 0.782-0.929. When the pivotal point of CI-AKI diagnosis was 6,327.755 pg/ml, the specificity was 85.7% and the sensitivity was 73.7%. Univariate analysis showed that the Scr concentration was positively correlated with the urinary KIM-1 level during the time prior to the procedure and 24 and 48 h after the procedure. In conclusion, the urinary KIM-1 may be a potential indicator for the early diagnosis of CI-AKI.

Dynamic Contrast-Enhanced MRI Using a Macromolecular MR Contrast Agent (P792): Evaluation of Antivascular Drug Effect in a Rabbit VX2 Liver Tumor Model.

ObjectiveTo evaluate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using macromolecular contrast agent (P792) for assessment of vascular disrupting drug effect in rabbit VX2 liver tumor models.Materials and MethodsThis study was approved by our Institutional Animal Care and Use Committee. DCE-MRI was performed with 3-T scanner in 13 VX2 liver tumor-bearing rabbits, before, 4 hours after, and 24 hours after administration of vascular disrupting agent (VDA), using gadomelitol (P792, n = 7) or low molecular weight contrast agent (gadoterate meglumine [Gd-DOTA], n = 6). P792 was injected at a of dose 0.05 mmol/kg, while that of Gd-DOTA was 0.2 mmol/kg. DCE-MRI parameters including volume transfer coefficient (Ktrans) and initial area under the gadolinium concentration-time curve until 60 seconds (iAUC) of tumors were compared between the 2 groups at each time point. DCE-MRI parameters were correlated with tumor histopathology. Reproducibility in measurement of DCE-MRI parameters and image quality of source MR were compared between groups.ResultsP792 group showed a more prominent decrease in Ktrans and iAUC at 4 hours and 24 hours, as compared to the Gd-DOTA group. Changes in DCE-MRI parameters showed a weak correlation with histologic parameters (necrotic fraction and microvessel density) in both groups. Reproducibility of DCE-MRI parameters and overall image quality was not significantly better in the P792 group, as compared to the Gd-DOTA group.ConclusionDynamic contrast-enhanced magnetic resonance imaging using a macromolecular contrast agent shows changes of hepatic perfusion more clearly after administration of the VDA. Gadolinium was required at smaller doses than a low molecular contrast agent.

Contrast-Enhanced Ultrasound

The recent decade has witnessed the great improvement of contrast-enhanced ultrasound (CEUS) and its extensive use in clinical practice, which is undoubtedly the major breakthrough in the field of diagnostic ultrasound in recent years. The concept of CEUS can be looked back to 60s in the last century, whereas only in 2000s CEUS regained increasing attention in both clinical practice and basic research. The current popularization of CEUS is largely due to the emergence of low acoustic power contrast-specific imaging mode and microbubble-based contrast agent filled with inert gas. After administration of ultrasound contrast agent intravenously, the low acoustic power contrast-specific imaging mode facilitates visualization of the nonlinear signals from the microbubbles in the circulation and suppresses the linear signals from the surrounding tissues, which leads to an improved signal-to-noise ratio and facilitates depiction of macro- and microcirculation of the region of interest (ROI) noninvasively. The low acoustic power also limits the damage to the microbubbles under acoustic push; thus, more microbubbles will remain in the circulation and a long time CEUS depiction is available [1].

Preliminary study of low-dose CT coronary angiography by using low concentration isotonic contrast agent

Objective To compare the iodine intake,image quality and radiation dose of dual-source CT coronary artery angiography between the low concentration isotonic contrast agent with iterative reconstruction technique of sinogram affirmed iterative rEconstruction (SAFIRE) and common concentration contrast agent with filtered back projection (FBP).Methods One hundred patients [58 men,42 women; age:(62± 11)y] were enrolled in this study.Fifty consecutive patients (Group A) were scanned with FBP and common concentration contrast agent and another 50 consecutive patients (Group B) were scanned with low concentration isotonic contrast agent and iterative reconstruction technique.The image quality were assessed by two experienced radiologists with a double blinded fashion in a five score scale.The attenuation of coronary artery,scan time,imaging noise,signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR),radiation dose and iodine intake between these two groups were compared using two sample t test.The observer agreement for image quality was calculated using Kappa statistics.Results All examinations were completed successfully.There was no statistical difference (P＞0.05) between two groups in clinical characteristics and scan parameters.There was no statistical difference for the mean subjective image quality of group A (4.4±0.7) and group B (4.3±0.8) (t=0.924,P＞0.05).The Kappa value between two radiologists was 0.887 (P＜0.01)on image quality.The mean attenuation of coronary artery segments was higher than 300 HU,especially in group A (386.1±51.5) HU,which was slightly higher than the group B (384.1±77.1) HU,but there was no statistical difference (t=0.157,P＞0.05).The SNR and CNR in two groups did not have significant differences (P＞0.05).The total iodine and iodine injection rates were 21.0 g,17.5 g/s in Group A and 16.2 g,13.5 g/s in Group B,respectively.The iodine intake was decreased by 22.9％ in Group B.The effective radiation dose in Group B (1.09±0.19) mSv was significantly (t=20.260,P＜0.01) lower than that in Group A (2.85±0.59) mSv,with the radiation dose reduced by 61.8％.Conclusion Low concentration isotonic contrast agent and iterative reconstruction technique can significantly reduce the radiation dose and iodine intake in CT coronary artery angiography and achieve the same image quality using common concentration contrast agent with FBP. Key words: Contrast media; Tomography, X-ray computed; Radiation dosage; Comparative study

Digital subtraction MR angiography roadmapping for magnetic steerable catheter tracking.

To develop a high temporal resolution MR imaging technique that could be used with magnetically assisted remote control (MARC) endovascular catheters. A technique is proposed based on selective intra-arterial injections of dilute MR contrast at the beginning of a fluoroscopic MR angiography acquisition. The initial bolus of contrast is used to establish a vascular roadmap upon which MARC catheters can be tracked. The contrast to noise ratio (CNR) of the achieved roadmap was assessed in phantoms and in a swine animal model. The ability of the technique to permit navigation of activated MARC catheters through arterial branch points was evaluated. The roadmapping mode proved effective in phantoms for tracking objects and achieved a CNR of 35.7 between the intra- and extra-vascular space. In vivo, the intra-arterial enhancement strategy produced roadmaps with a CNR of 42.0. The artifact produced by MARC catheter activation provided signal enhancement patterns on the roadmap that experienced interventionalists could track through vascular structures. A roadmapping approach with intra-arterial contrast-enhanced MR angiography is introduced for navigating the MARC catheter. The technique mitigates the artifact produced by the MARC catheter, greatly limits the required specific absorption rate, permits regular roadmap updates due to the low contrast agent requirements, and proved effective in the in vivo setting. Inc.

Milk - An Effective Low-Attenuation Computed Tomography Oral Contrast Medium

Background: To evaluate gastrointestinal pathology in computed tomography (CT) scan, optimum distention, mural visualization and gastrointestinal tract discrimination are necessary. High attenuation oral contrast material in the form of iodine solution has drawbacks in mural visualization and tolerance. Milk can be used as a low attenuation CT oral contrast agent in gastrointestinal tract discrimination and mural visualization with better tolerance. Objective: The purpose of our study was to compare the effectiveness, cost, and tolerance of milk and iopamiro (iodinated positive contrast medium) in patients undergoing abdominal CT with oral and IV contrast media. Materials and Methods: Two hundred and twelve patients were purposively assigned to receive either whole milk (n = 110) or iopamiro (n = 100). Results were independently reviewed by radiologists. Degree of bowel distention, mural visualization and gastrointestinal tract discrimination were qualitatively scored on a 4- point scale. A questionnaire regarding oral contrast tolerability was provided to each patient. Cost comparison of the two agents was performed. Results: No statistically significant differences were seen between whole milk and iopamiro with respect to degree of bowel distention and gastrointestinal tract discrimination for all segments of bowel studied (p &gt; 0.05). Mural visualization is better with whole milk compared with iopamiro (p &lt; 0.05). Significantly more patients ranked milk as pleasant in taste compared with iopamiro (p &lt; 0.05). Milk was better tolerated than iopamiro, with fewer gastrointestinal side effects, including abdominal discomfort (p = 0.065), cramping (p = 0.309), nausea (p = 0.001), vomiting (p = 0.003) and diarrhea (p = 0.347). The cost per patient for iopamiro is 900 BDT compared with 60 BDT for milk. Conclusion: Whole milk is comparable to iopamiro with respect to bowel distention and gastrointestinal tract discrimination and better in bowel wall visualization and has better patient acceptance, and fewer adverse symptoms. Milk is a costeffective alternative to iopamiro as a low-attenuation CT oral contrast agent. Journal of Enam Medical College; Vol 3 No 2 July 2013; Page 71-76 DOI: http://dx.doi.org/10.3329/jemc.v3i2.16126

Parametric imaging with contrast-enhanced ultrasound: Usefulness for characterization of dynamic effects of microvascularization for hepatocellular carcinoma and focal nodular hyperplasia

To evaluate whether parametric imaging with contrast-enhanced ultrasound (CEUS) is equal to experienced radiologists after review of CEUS in differentiating hepatocellular carcinoma (HCC) from focal nodular hyperplasia (FNH). An image processing software was used to quantitatively analyze the CEUS clips of 30 HCCs (mean diameter, 3.4±0.9 cm; range, 1.8-5.0 cm) and 30 FNHs (mean diameter, 3.0±1.1 cm; range, 1.1-5.0 cm). Low mechanical index contrast specific imaging modes and contrast agent of SonoVue® were applied for CEUS. Fourteen HCCs were pathologically diagnosed and 16 were clinically diagnosed, whereas all the FNHs were confirmed by pathological examination. Quantitative parameters of HCC and FNH were compared. The diagnostic performance between parametric imaging and two experienced readers was compared using the receiver operating characteristic (ROC) curve analysis. On parametric imaging, the rise time, time to peak and mean transit time for HCC and FNH were 16.7±11.1 s vs. 21.9±9.0 s (P=0.052), 29.9±14.1 s vs. 33.2±11.1 s (P=0.322), 115.0±90.9 s vs. 271.5±147.6 s (P<0.001), respectively. The ROC analysis showed that, for the differentiation between HCC and FNH, the cut-off point for mTT was 107.93 s with the Az value of 0.817 (95% CI: 0.703-0.931), and the Az value was 0.834 (95%CI: 0.728-0.941) for two experienced readers (P=0.417 compared with mTT). The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were 96.7%, 66.7%, 81.7%, 74.4%, and 95.2%, respectively, for parametric imaging, and 86.7%, 76.7%, 81.7%, 78.8%, and 85.2%, respectively, for two experienced readers (all P>0.05 compared with parametric imaging). Parametric imaging with CEUS is helpful for characterization the typical dynamic effects of microvascularization of HCC and FHH and is equal to experienced readers in the differential diagnosis between HCC and FNH.

Low-Contrast Agent Dose Dual-Energy CT Monochromatic Imaging in Pulmonary Angiography Versus Routine CT

This study aimed to retrospectively evaluate the feasibility and reliability of low-contrast agent dose dual-energy computed tomography (DECT) monochromatic imaging in pulmonary angiography. Computed tomography pulmonary angiography was performed in 86 patients, 41 in 120-kVp computed tomography (CT) and 45 in DECT with low-contrast agent dose. The images in DECT were reconstructed at optimal kiloelectron-voltage (keV), demonstrating the best contrast-to-noise ratio between pulmonary artery and soft tissue, and at 70 keV. Image quality was compared by quantitative and subjective indexes. The radiation doses were recorded. Compared with 120-kVp CT, optimal keV showed superior quantitative indexes with inferior subjective image quality, whereas 70 keV demonstrated no statistical difference in quantitative indexes with superior subjective image quality. All suspicious pulmonary embolisms in DECT were diagnosed confidently by combination of 2 kinds of monochromatic imaging. The radiation dose in DECT is almost twice as 120-kVp CT. Low-contrast agent dose DECT monochromatic imaging in pulmonary angiography accommodates superior intravascular enhancement and contrast in pulmonary arteries, and improves diagnostic confidence with compatible radiation dose.

Phospholipid micelle encapsulated gadolinium oxide nanoparticles for imaging and gene delivery.

We encapsulated gadolinium oxide (Gd2O3) nanoparticles within phospholipid micelles as a novel low cytotoxic T1-weighted MRI imaging contrast agent (MGdNPs) that can also deliver small molecules such as DNA plasmids. MGdNPs show relatively good MRI relaxivity values, negligible cytotoxicity, excellent cellular uptake and expression of DNA plasmids in vivo. Biodistribution studies in mice show that intranasal and intraperitoneal administration of MGdNPs can effectively target specific organs.

RISK SCORE FOR PREDICTION OF CONTRAST INDUCED NEPHROPATHY IN HAN CHINESE UNDERWENT PERCUTANEOUS CORONARY INTERVENTION

ObjectivesTo develop a simplified risk score of contrast induced nephropathy (CIN) after percutaneous coronary intervention (PCI) for Han Chinese.MethodsA retrospective study was performed on 1500 patients for the development dataset,...

Low Contrast Agent and Radiation Dose Protocol for Hepatic Dynamic CT of Thin Adults at 256–Detector Row CT: Effect of Low Tube Voltage and Hybrid Iterative Reconstruction Algorithm on Image Quality

To evaluate the effect on image quality of a low contrast agent dose and radiation dose protocol at abdominal dynamic computed tomography (CT) with a low tube voltage, hybrid iterative reconstruction algorithm, and a 256- detector row scanner. This prospective study received institutional review board approval, and prior informed written consent was obtained from all patients. Seventy-four patients undergoing hepatic dynamic CT were randomly assigned to one of two protocols: Thirty-nine patients underwent scanning with the conventional 120-kVp protocol and the other 35 patients underwent scanning with an 80-kVp tube voltage and a 40% reduction in contrast agent dose. The 80-kVp images were also postprocessed with a hybrid iterative reconstruction algorithm. The estimated effective radiation dose of each protocol was compared and the image noise and contrast-to-noise-ratio (CNR) of the 120-kVp, 80-kVp, and hybrid iterative reconstructed 80-kVp images were evaluated by using the Student t test. The effective radiation dose was 51% lower during the hepatic arterial phase (HAP) and 48% lower during the portal venous phase (PVP) with the 80-kVp protocol than with the 120-kVp protocol (HAP: 5.6 mSv ± 1.0 [standard deviation] vs 11.6 mSv ± 3.3; PVP: 5.8 mSv ± 0.7 vs 11.2 mSv ± 3.2, respectively). The hybrid iterative reconstruction decreased image noise by 23% during the HAP (9.2 ± 1.9 vs 12.0 ± 2.6) and by 24% during the PVP (9.4 ± 1.8 vs 12.3 ± 2.6). There were no significant differences in the CNR of any of the regions of interest between 80-kVp with iterative reconstruction and 120-kVp protocols (P = .46-.85). A low tube voltage and the hybrid iterative reconstruction algorithm can dramatically decrease radiation and contrast agent doses with adequate image quality at hepatic dynamic CT of thin adults with use of a 256-detector row scanner.

Mini‐STAR as bail‐out strategy for percutaneous coronary intervention of chronic total occlusion

Although the advancement of the equipment and the presence of innovative techniques, percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) continues to be affected by lower procedural success in comparison with non occluded vessel PCI. We describe a new technique for the treatment of coronary CTO which utilizes a new generation of polymeric wires. From March 2009 to June 2010 different strategies were adopted as "bail out" after an initial attempt failed in 117 consecutive CTO lesions. Among these, conventional strategies (CS) such as parallel wire, sub-intimal tracking and re-entry (STAR), microchannel technique, intracoronary ultrasound guided revascularization and anchor balloon, were used in 75 cases (64.1%), while in the remaining a new technique, the "mini-STAR," was used (39.9%). Although no substantial differences were observed regarding the distribution of clinical features and angiographic lesions characteristics between the populations, mini-STAR was able to achieve a higher rate of procedural success in comparison with other CS (97.6% vs. 52%, P < 0.001) with lower contrast agent use (442 ± 259 cm(3) vs. 561 ± 243 cm(3), P = 0.01) and shorter procedural and fluoroscopy times (122 ± 61 vs. 157 ± 74 min, P = 0.009 and 60 ± 31 min vs. 75 ± 38 min, P = 0.03, respectively). No differences were observed in term of peri-procedural complications such as procedural myocardial infarction, coronary perforations, and contrast-induced nephropathy between mini-STAR and CS. The mini-STAR technique is a promising strategy for the treatment of CTO lesions, achieving a high procedural success rate and low occurrence of procedural adverse events.

Risk score for prediction of contrast induce nephropathy in patients underwent percutaneous coronary intervention

ObjectiveTo develop a simplified risk score of contrast induced nephropathy (CIN) after percutaneous coronary intervention (PCI).MethodsA retrospective study was performed on 1500 patients for the development dataset, who had undergone...

Effects of Microbial Populations on Anthocyanin Profile of Sangiovese Wines Produced in Tuscany, Italy

<h3>Objectives</h3> To develop a simplified risk score of contrast induced nephropathy (CIN) after percutaneous coronary intervention (PCI) for Han Chinese. <h3>Methods</h3> A retrospective study was performed on 1500 patients for the development dataset, who had undergone PCI from January 2008 to May 2010. And one thousand patients treated in the same period were selected for the validation set. Logistic regression analysis was applied to identify risk factors for CIN. Based on the OR, the sum of the integers was a total risk score for each patient. <h3>Results</h3> (1) Among the 1500 patients, CIN occurred in 246 patients and the overall incidence of CIN was 16.4%. (2) Eleven identified variables were identified as risk factors for CIN (with weighted integer): diabetes (3 score), hypotension (3 score), Left ventricular ejection fraction (LVEF≤45%) (3 score), eGFR &lt;60 ml/min/1.73 m² (3 score), age&gt;70 years (2 score), myocardial infarction (2 score), emergency PCI (2 score), anaemia (2 score), decreased high-density lipoprotein (HDL) concentration (&lt;1 mmol/l) (2 score), contrast agent dose of &gt;200 ml (2 score), low permeability contrast agent (1 score). (3) The sum of the integers was a total risk score for each patient. The incidence of CIN was 5.2% in low risk group (≤4), 13.6% in the moderate risk group (5–10), 32.3% in the high risk group (11–14) and 59.0% in the very high risk group (≥15). (4) The model demonstrated good discriminative power in the validation population, showing that the increasing risk score was strongly associated with CIN (c-statistic=0.82). <h3>Conclusions</h3> This simple scoring system proposed here provides a good estimate of the risk of CIN after PCI for Han Chinese. This risk score can be used for the prevention and treatment of CIN.

Abdominal Dynamic CT in Patients with Renal Dysfunction: Contrast Agent Dose Reduction with Low Tube Voltage and High Tube Current–Time Product Settings at 256–Detector Row CT

To evaluate the feasibility of a low-contrast agent dose protocol at abdominal dynamic computed tomography (CT) with a low tube voltage high tube current-time product technique and a 256-detector row CT unit. This prospective study received institutional review board approval; written informed consent to participate was obtained from all patients. The study included 151 patients; 117 had an estimated glomerular filtration rate (eGFR) greater than or equal to 60 mL/min/1.73 m(2). These patients were examined with the conventional 120-kVp protocol. The other 34 patients underwent scanning with an 80-kVp tube voltage, a high tube current-time product, and a 40% reduction in contrast agent dose. Effective dose (ED), image noise, attenuation, contrast-to-noise ratio (CNR), and figure of merit of the aorta in the arterial phase and of the portal vein and hepatic parenchyma in the portal venous phase in the two groups were compared with the Student t test. Estimated ED was about 20% lower with the 80-kVp protocol than with the 120-kVp protocol. There were no significant differences in CNR in any region of interest between the 80-kVp protocol and the 120-kVp protocol (abdominal aorta: 36.9 ± 9.7 [standard deviation] vs 36.1 ± 8.1, P = .63; portal vein: 13.4 ± 3.2 vs 13.1 ± 3.2, P = .65; hepatic parenchyma: 6.4 ± 2.6 vs 6.7 ± 2.3, P = .51). Contrast dose at hepatic dynamic 256-detector row CT in patients with renal dysfunction can be decreased by 40% with this protocol by using the 80-kVp setting and a high tube current-time product.