Grams Of Iodine Research Articles

Lean body weight-adjusted intravenous iodinated contrast dose for abdominal CT in dogs reduces interpatient enhancement variability while providing diagnostic quality organ enhancement.

Contrast-enhanced computed tomography (CECT) is increasingly used to screen for abdominal pathology in dogs, and the contrast dose used is commonly calculated as a linear function of total body weight (TBW). Body fat is not metabolically active and contributes little to dispersing or diluting contrast medium (CM) in the blood. This prospective, analytic, cross-section design pilot study aimed to establish the feasibility of intravenous CM dosed according to lean body weight (LBW) for abdominal CECT in dogs compared to TBW. We hypothesized that when dosing intravenous CM according to LBW, studies will remain at diagnostic quality, there will be a reduced interindividual contrast enhancement (CE) variability, and there will be less change to heart rate and blood pressure in dogs compared to when administering CM calculated on TBW. Twelve dogs had two CECT studies with contrast doses according to TBW and LBW at least 8weeks apart. Interindividual organ and vessel CE variability, diagnostic quality of the studies, and changes in physiological status were compared between protocols. The LBW-based protocol provided less variability in the CE of most organs and vessels (except the aorta). When dosed according to LBW, liver enhancement was positively associated with grams of iodine per kg TBW during the portal venous phase (P=0.046). There was no significant difference in physiological parameters after CM administration between dosing protocols. Our conclusion is that a CM dose based on LBW for abdominal CECT lowers interindividual CE variability and is effective at maintaining studies of diagnostic quality.

Liver Enhancement on Computed Tomography Is Suboptimal in Patients with Liver Steatosis.

This study’s aim was twofold. Firstly, to assess liver enhancement quantitatively and qualitatively in steatotic livers compared to non-steatotic livers on portal venous computed tomography (CT). Secondly, to determine the injection volume of contrast medium in patients with severe hepatic steatosis to improve the image quality of the portal venous phase. We retrospectively included patients with non-steatotic (n = 70), the control group, and steatotic livers (n = 35) who underwent multiphase computed tomography between March 2016 and September 2020. Liver enhancement was determined by the difference in attenuation in Hounsfield units (HU) between the pre-contrast and the portal venous phase, using region of interests during in three different segments. Liver steatosis was determined by a mean attenuation of ≤40 HU on unenhanced CT. Adequate enhancement was objectively defined as ≥50 ΔHU and subjectively using a three-point Likert scale. Enhancement of non-steatotic and steatotic livers were compared and associations between enhancement and patient- and scan characteristics were analysed. Enhancement was significantly higher among the control group (mean 51.9 ± standard deviation 11.5 HU) compared to the steatosis group (40.6 ± 8.4 HU p for difference < 0.001). Qualitative analysis indicated less adequate enhancement in the steatosis group: 65.7% of the control group was rated as good vs. 8.6% of the steatosis group. We observed a significant correlation between enhancement, and presence/absence of steatosis and grams of iodine per total body weight (TBW) (p < 0.001; adjusted R2 = 0.303). Deduced from this correlation, theoretical contrast dosing in grams of Iodine (g I) can be calculated: g I = 0.502 × TBW for non-steatotic livers and g I = 0.658 × TBW for steatotic livers. Objective and subjective enhancement during CT portal phase were significantly lower in steatotic livers compared to non-steatotic livers, which may have consequences for detectability and contrast dosing.

15-Hydroxyprostaglandin dehydrogenase inhibitor prevents contrast-induced acute kidney injury

The two primary mechanisms by which iodinated contrast media (CM) causes contrast-induced acute kidney injury (CIAKI) are the hemodynamic effect causing intrarenal vasoconstriction and the tubular toxic effect causing acute tubular necrosis. Inhibition of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), which degrades prostaglandin E2 (PGE2), promotes tissue repair and regeneration in many organs. PGE2 causes intrarenal arterial vasodilation. In this study, we investigated whether a 15-PGDH inhibitor can act as a candidate for blocking these two major mechanisms of CIAKI. We established a CIAKI mouse model by injecting a 10 gram of iodine per body weight (gI/kg) dose of iodixanol into each mouse tail vein. A 15-PGDH inhibitor (SW033291), PGE1, or PGE2 were administered to compare the renal functional parameters, histologic injury, vasoconstriction, and renal blood flow changes. In addition, human renal proximal tubular epithelial cells were cultured in a CM-treated medium. SW033291, PGE1, or PGE2 were added to compare any changes in cell viability and apoptosis rate. CIAKI mice that received SW033291 had lower serum levels of creatinine, neutrophil gelatinase-associated lipocalin, and kidney injury molecule 1 (p < 0.001); lower histologic injury score and TUNEL positive rates (p < 0.001); and higher medullary arteriolar area (p < 0.05) and renal blood flow (p < 0.001) than CM + vehicle group. In cell culture experiments, Adding SW033291 increased the viability rate (p < 0.05) and decreased the apoptosis rate of the tubular epithelial cells (p < 0.001). This 15-PGDH inhibitor blocks the two primary mechanisms of CIAKI, intrarenal vasoconstriction and tubular cell toxicity, and thus has the potential to be a novel prophylaxis for CIAKI. Abbreviations: 15-PGDH: 15-hydroxyprostaglandin dehydrogenase; AMP: adenosine monophosphate; CIAKI: contrast-induced acute kidney injury; CM: contrast media; EP: prostaglandin E2 receptor; hRPTECs: human-derived renal proximal tubule epithelial cells; KIM-1: kidney injury molecule-1; MTT: 3-(4,5-Dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide; NGAL: neutrophil gelatinase-associated lipocalin; PBS: phosphate-buffered saline; PGE1: prostaglandin E1; PGE2: prostaglandin E2; RBF: renal blood flow; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling; α-SMA: α-Smooth muscle actin

The aortic and hepatic contrast enhancement at CT and its correlations with various body size index

Objective To evaluate the effect of height (HT), total body weight (TBW), body mass index (BMI), lean body weight (LBW), body surface area (BSA) and blood volume (BV) on aortic and liver contrast enhancement during upper abdominal contrast-enhanced CT scans. Methods One hundred and thirteen enrolled patients underwent upper abdominal multiphase contrast-enhanced CT scans. The enhancement (ΔHU) of aorta in hepatic arterial phase and liver parenchyma in portal venous phase were measured and calculated. The ΔHU values difference of aorta and liver parenchyma in subgroups between males and females, TBW<60 kg and TBW≥60 kg, BMI<25 kg/m2 and BMI≥25 kg/m2 were compared. To evaluate the effect of the patient′s body parameters on aortic and hepatic enhancement, we performed simple linear regression analyses between the change in CT numbers per gram of iodine (ΔHU/gI) at aorta and liver and each of the following: HT, TBW, BMI, LBW, BSA, and BV. Pearson and t test were used. Results The mean ΔHU values of aorta and liver were significantly lower at males than that of at females (P<0.05). They were higher at TBW<60 kg patients than at TBW≥60 kg patients(P<0.05), and the mean ΔHU values of the liver at BMI<25 kg/m2 patients were significantly higher than at BMI≥25 kg/m2 patients(P<0.05). The proportion of the ΔHU values at liver less than 50 HU was higher at males (18.3%, 11/60) than at females (7.5%, 4/53). The most obvious negative correlation coefficients were found between the ΔHU/gI of aorta and LBW at hepatic arterial phase (r=-0.559, P<0.01), and between the ΔHU/gI of liver and BSA at portal venous phase (r=-0.680, P<0.01). Conclusion LBW or BSA could be the alternative body index to TBW for the calculation of personalized iodine dose protocol at aortic and liver enhanced CT scans. Key words: Contrast media; Tomography, X-ray computed; Aorta; Liver

Optimizing Pulmonary Embolism Computed Tomography in the Age of Individualized Medicine: A Prospective Clinical Study.

The aim of the study was to simultaneously optimize contrast media (CM) injection and scan parameters for the individual patient during computed tomography pulmonary angiography (CTPA). In this study (NCT02611115), 235 consecutive patients suspected of having pulmonary embolism were prospectively enrolled. Automated kV selection software on a third-generation multidetector computed tomography adapted tube voltage to the individual patient, based on scout scans. The contrast injection protocol was adapted to both patient body weight and kV-setting selection via a predefined formula, based on previous research. Injection data were collected from a contrast media and radiation dose monitoring software. Attenuation was measured in Hounsfield units (HU) in the pulmonary trunk (PT); attenuation values 200 HU or greater were considered diagnostic. Subjective image quality was assessed by using a 4-point Likert scale at the level of the PT, lobar, segmental, and subsegmental arteries. Results between groups were reported as mean ± SD. Two hundred twenty-two patients (94%) were scanned at a kV setting below 100 kV: n = 108 for 70 kV, n = 82 for 80 kV, and n = 32 for 90 kV. Mean CM bolus volume (in milliliters) and total iodine load (in grams of iodine) for 70 to 90 kV were as follows: 24 ± 3 mL and 7 ± 1 g I, 29 ± 4 mL and 9 ± 2 g I, and 38 ± 4 mL and 11 ± 1 g I, respectively. Mean flow rates (in milliliters per second) and iodine delivery rates (in grams of iodine per second) were 3.0 ± 0.4 mL/s and 0.9 ± 0.1 g I/s (70 kV), 3.6 ± 0.4 mL/s and 1.0 ± 0.1 g I/s (80 kV), and 4.7 ± 0.5 mL/s and 1.3 ± 0.1 g I/s (90 kV). Mean radiation doses were 1.3 ± 0.3 mSv at 70 kV, 1.7 ± 0.4 mSv at 80 kV, and 2.2 ± 0.6 mSv at 90 kV. Mean vascular attenuation in the PT for each kV group was as follows: 397 ± 101 HU for 70 kV, 398 ± 96 HU for 80 kV, and 378 ± 100 HU for 90 kV, P = 0.59. Forty-six patients (21%) showed pulmonary embolism on the CTPA. One scan (90 kV) showed nondiagnostic segmental pulmonary arteries, and 5% of subsegmental arteries were of nondiagnostic image quality. All other segments were considered diagnostic-excellent subjective image quality. Simultaneously optimizing both CM injections and kV settings to the individual patient in CTPA results in diagnostic attenuation with on average 24 to 38 mL of CM volume and a low radiation dose for most patients. This individualized protocol may help overcome attenuation-variation problems between patients and kV settings in CTPA.

Development and Validation of Generalized Linear Regression Models to Predict Vessel Enhancement on Coronary CT Angiography.

ObjectiveWe evaluated the effect of various patient characteristics and time-density curve (TDC)-factors on the test bolus-affected vessel enhancement on coronary computed tomography angiography (CCTA). We also assessed the value of generalized linear regression models (GLMs) for predicting enhancement on CCTA.Materials and MethodsWe performed univariate and multivariate regression analysis to evaluate the effect of patient characteristics and to compare contrast enhancement per gram of iodine on test bolus (ΔHUTEST) and CCTA (ΔHUCCTA). We developed GLMs to predict ΔHUCCTA. GLMs including independent variables were validated with 6-fold cross-validation using the correlation coefficient and Bland–Altman analysis.ResultsIn multivariate analysis, only total body weight (TBW) and ΔHUTEST maintained their independent predictive value (p < 0.001). In validation analysis, the highest correlation coefficient between ΔHUCCTA and the prediction values was seen in the GLM (r = 0.75), followed by TDC (r = 0.69) and TBW (r = 0.62). The lowest Bland–Altman limit of agreement was observed with GLM-3 (mean difference, −0.0 ± 5.1 Hounsfield units/grams of iodine [HU/gI]; 95% confidence interval [CI], −10.1, 10.1), followed by ΔHUCCTA (−0.0 ± 5.9 HU/gI; 95% CI, −11.9, 11.9) and TBW (1.1 ± 6.2 HU/gI; 95% CI, −11.2, 13.4).ConclusionWe demonstrated that the patient's TBW and ΔHUTEST significantly affected contrast enhancement on CCTA images and that the combined use of clinical information and test bolus results is useful for predicting aortic enhancement.

Prediction of Edible-oil Iodine Values Based on Raman and near Infrared Spectroscopy

Based on Raman and near infrared spectroscopy (NIR), the modeling of edible-oil iodine value was conducted following chemometrics and support vector machine regression (SVR). The Raman and NIR spectral data of 44 oil samples were collected and preprocessed. The preprocessed spectral data at characteristic wavelengths were extracted with CARS and iPLS methods. Parameter optimization was performed following the grid search algorithm (GS), for the SVR iodine value prediction models. The results show that all the models built could predict the iodine values to some extent. An NIR-MSC-iPLS-SVR model exhibited the greatest stability and its correlation coefficient R of the prediction set reached 97.69%. The results show that NIR has more advantages in the fast prediction of iodine values and can be utilized to manufacture portable spectral instruments for edible-oil iodine-value determination. Vegetable oils can afford human body unsaturated fatty acids, vitamins, and other nutrients [1]. Wherein, the unsaturated fatty acids can ensure the physiological function of cells, reduce cholesterol contents, and perfect blood circulation [2]. The unsaturated fatty acid content can be indicated by unsaturation degree and iodine value (iodine number). The iodine value refers to the grams of iodine consumed in the addition reaction of 100 g of oil. The higher the iodine value is, the greater the unsaturation degree is, and the higher the unsaturated fatty acid content is. The iodine value determination methods include Wijs method (national standard), high-performance liquid chromatography (HPLC) method, and so forth [3-4]. Wherein, the Wijs method is precise and commonly used. Nevertheless, because the sample and titrant solution are immiscible, at the end point of titration, the color change is too slow. And, the method is tedious and requires a large amount of hazardous organic solvents [5-6]. Compared with the Wijs method, the spectral method is fast, efficient, and free of sample pretreatment. Hence, it has been increasingly used in oil and food industries [7]. Yu Yanbo et al. [8] used near infrared spectroscopy (NIR) technology to build a prediction model for the prediction of contents of 4 fatty acids in vegetable oils. María Á. Carmona et al. [9] identified oils and determined iodine values based on Raman spectroscopy.

MDCT of the liver in obese patients: evaluation of a different method to optimize iodine dose.

To prospectively compare two different approaches for estimating the amount of intravenous contrast media (CM) needed for multiphasic MDCT of the liver in obese patients. This single-center, HIPAA-compliant prospective study was approved by our Institutional Review Board. Ninety-six patients (55 men, 41 women), with a total of 42 hypovascular liver lesions, underwent MDCT of the liver. The amount of contrast medium injected was computed according to the patient's lean body weight which was estimated using either a bioimpedance device (Group A) or the James formula (Group B). The following variables were compared between the two groups: the amount of contrast medium injected (in grams of Iodine, gI), the contrast enhancement index (CEI) and the lesion-to-liver contrast-to-noise ratio. Protocols A and B yielded significant differences in the amount of CM injected (mean values 41.9±4.41 gI in Group A vs. 35.9±5.75 gI in Group B; P=0.021). The mean CEI value and lesion-to-liver contrast-to-noise ratio measured on the portal phase were significantly higher with protocol A than with protocol B (P<0.05). Our study shows that the adoption of a bioimpedance device in obese patients improves liver parenchymal enhancement and lesion conspicuity.

Aortic and Hepatic Contrast Enhancement During Hepatic-Arterial and Portal Venous Phase Computed Tomography Scanning: Multivariate Linear Regression Analysis Using Age, Sex, Total Body Weight, Height, and Cardiac Output.

We evaluated the effect of the age, sex, total body weight (TBW), height (HT) and cardiac output (CO) of patients on aortic and hepatic contrast enhancement during hepatic-arterial phase (HAP) and portal venous phase (PVP) computed tomography (CT) scanning. This prospective study received institutional review board approval; prior informed consent to participate was obtained from all 168 patients. All were examined using our routine protocol; the contrast material was 600 mg/kg iodine. Cardiac output was measured with a portable electrical velocimeter within 5 minutes of starting the CT scan. We calculated contrast enhancement (per gram of iodine: [INCREMENT]HU/gI) of the abdominal aorta during the HAP and of the liver parenchyma during the PVP. We performed univariate and multivariate linear regression analysis between all patient characteristics and the [INCREMENT]HU/gI of aortic- and liver parenchymal enhancement. Univariate linear regression analysis demonstrated statistically significant correlations between the [INCREMENT]HU/gI and the age, sex, TBW, HT, and CO (all P < 0.001). However, multivariate linear regression analysis showed that only the TBW and CO were of independent predictive value (P < 0.001). Also, only the CO was independently and negatively related to aortic enhancement during HAP and to liver parenchymal enhancement when the contrast material injection protocol was adjusted for the TBW (P < 0.001). By multivariate linear regression analysis only the TBW and CO were significantly correlated with aortic and liver parenchymal enhancement; the age, sex, and HT were not. The CO was the only independent factor affecting aortic and liver parenchymal enhancement at hepatic CT when the protocol was adjusted for the TBW.

The Optimal Body Size Index with Which to Determine Iodine Dose for Hepatic Dynamic CT: A Prospective Multicenter Study.

To identify the body size parameter that exhibits the best correlation with aortic and hepatic enhancement at hepatic dynamic computed tomography (CT) in a large patient population enrolled in a multicenter study. This prospective study was approved by the ethics committee of each of the 31 participating institutions where 1342 patients were enrolled between April 2012 and September 2013. All patients provided either written or oral informed consent. All patients underwent hepatic dynamic CT, which included preenhanced, hepatic arterial phase (HAP), and portal venous phase (PVP) scanning, performed with the routine scanning protocol of each institution. Changes in CT number (in Hounsfield units) per gram of iodine in the aorta (eA/I) and liver (eL/I) during HAP and PVP scanning were recorded for each patient. Hierarchical multivariate linear regression analysis was performed in which the outcome variable was either eA/I or eL/I; the independent variables were age, sex, one body size parameter (height, body weight, body mass index, lean body weight [LBW], or body surface area), and liver function (aspartate aminotransferase, albumin, and total bilirubin levels). A two-level hierarchical model in which patients were level 1 and the institution was level 2 was used. Hierarchical multivariate linear regression analysis revealed that in the population not stratified by sex, body size was significantly correlated with eA/I and eL/I (P < .001) and that LBW exhibited the strongest correlation with eA/I and eL/I (r = -0.561 and r = -0.601, respectively). Sex-stratified analysis showed that LBW was more strongly correlated with eA/I and eL/I in women (r = -0.779 and r = -0.948, respectively) than in men (r = -0.500 and r = -0.494, respectively) or in the nonstratified total population. Among body size parameters, LBW exhibited the strongest correlation with aortic and hepatic enhancement, especially in women.

Influence of aromatic raw materials on the animal fat quality

Manufacture of new meat products requires paying attention to raw meat processing methods, aimed at ensuring the reliable spoilage protection, and performing precise control over the state, stability of food properties and preservation degree of quality indicators. Various natural or synthetic antioxidants are widely used for inhibition of oxidative processes in products. The degree of oxidative spoilage of fat was determined by peroxide number (number of grams of iodine, extracted from potassium iodide by peroxides, contained in 100 g of the product). Quantitative determination of the content of carbonyl compounds (aldehydes) was performed by determining the benzidine number based on measuring the color intensity that develops in the interaction of aldehydes with benzidine, shows the content of aldehydes in terms of cinnamic aldehyde in mg per 100 g of fat. To investigate the antioxidant properties of aromatic plants, 4 experimental samples were formed: control sample №1, containing 100 g of pork belly fat, black pepper and allspice in the ratio, g - 1: 0.9, sample №2 - 100 g of pork belly fat, black pepper: thyme: juniper - 0.9: 0.8: 0.1 g; sample №3 - 100 g of pork belly fat, black pepper: thyme: juniper - 0.9: 0.7: 0.2 g; sample №4 - 100 g of pork belly fat, black pepper: thyme: juniper - 0.9: 0.6: 0.3 g. Aromatic substances of thyme herb and juniper fruit combined with black pepper have better antioxidant properties than black pepper combined with allspice and increase the shelf life of animal fats by 2.1 times. In samples with higher concentrations of thyme, spoilage processes run slower (sample №2 - 100 g pork belly, black pepper: thyme: juniper - 0.9: 0.8: 0.1 g). Thus, replacement of allspice by juniper combined with black pepper guarantees efficient spoilage inhibition of animal fats, and, therefore, their use in the production technology of smoked sausages to lengthen shelf life is possible.

Visualization of Dialysis Fistula by Computed Tomography Using Time-Resolved 3D Volume Rendering

To evaluate the function of arteriovenous (AV) dialysis fistula using dynamic computed tomography (CT) and time-resolved 3-dimensional (3D) volume rendering (VR). Seven patients referred for angiographic CT examination of the AV dialysis fistula were enrolled. Twenty-four grams of iodine were administered intravenously (iomeprol 400 mg I/mL at 6 mL/sec) followed by a 50-mL saline flush. Dynamic scanning was performed for 15-24 sec. CT images were then postprocessed on a dedicated workstation creating time-resolved 3D VR images and movies. All studies showed good image quality showing pathology in 6 of 7 patients. Unexpected findings were observed in 1 patient, aneurysm (n = 1). Radiation dose was 5 mSv. The function of AV dialysis fistula can be visualized using dynamic CT and time-resolved 3D VR.

Intravascular Enhancement With Identical Iodine Delivery Rate Using Different Iodine Contrast Media in a Circulation Phantom

Both iodine delivery rate (IDR) and iodine concentration are decisive factors for vascular enhancement in computed tomographic angiography. It is unclear, however, whether the use of high-iodine concentration contrast media is beneficial to lower iodine concentrations when IDR is kept identical. This study evaluates the effect of using different iodine concentrations on intravascular attenuation in a circulation phantom while maintaining a constant IDR. A circulation phantom with a low-pressure venous compartment and a high-pressure arterial compartment simulating physiological circulation parameters was used (heart rate, 60 beats per minute; stroke volume, 60 mL; blood pressure, 120/80 mm Hg). Maintaining a constant IDR (2.0 g/s) and a constant total iodine load (20 g), prewarmed (37°C) contrast media with differing iodine concentrations (240-400 mg/mL) were injected into the phantom using a double-headed power injector. Serial computed tomographic scans at the level of the ascending aorta (AA), the descending aorta (DA), and the left main coronary artery (LM) were obtained. Total amount of contrast volume (milliliters), iodine delivery (grams of iodine), peak flow rate (milliliter per second), and intravascular pressure (pounds per square inch) were monitored using a dedicated data acquisition program. Attenuation values in the AA, the DA, and the LM were constantly measured (Hounsfield unit [HU]). In addition, time-enhancement curves, aortic peak enhancement, and time to peak were determined. All contrast injection protocols resulted in similar attenuation values: the AA (516 [11] to 531 [37] HU), the DA (514 [17] to 531 [32] HU), and the LM (490 [10] to 507 [17] HU). No significant differences were found between the AA, the DA, and the LM for either peak enhancement (all P > 0.05) or mean time to peak (AA, 19.4 [0.58] to 20.1 [1.05] seconds; DA, 21.1 [1.0] to 21.4 [1.15] seconds; LM, 19.8 [0.58] to 20.1 [1.05] seconds). This phantom study demonstrates that constant injection parameters (IDR, overall iodine load) lead to robust enhancement patterns, regardless of the contrast material used. Higher iodine concentration itself does not lead to higher attenuation levels. These results may stimulate a shift in paradigm toward clinical usage of contrast media with lower iodine concentrations (eg, 240 mg iodine/mL) in individual tailored contrast protocols. The use of low-iodine concentration contrast media is desirable because of the lower viscosity and the resulting lower injection pressure.

Body size indices to determine iodine mass with contrast-enhanced multi-detector computed tomography of the upper abdomen: does body surface area outperform total body weight or lean body weight?

To compare total body weight (TBW), lean body weight (LBW) and body surface area (BSA) for the adjustment of the iodine dose required for contrast-enhanced multi-detector computed tomography (MDCT) of the aorta and the liver. One hundred and three patients undergoing MDCT of the abdomen were randomised into three groups: the TBW group receiving 0.6 g iodine/kg of TBW (n = 33), the LBW group receiving 0.75 g iodine/kg of LBW (n = 35) and the BSA group receiving 22 g iodine/m(2) (n = 35). ∆HU (increases in CT value) per gram of iodine (∆HU/g) and adjusted maximum hepatic enhancement (adjusted MHE; ∆HU/[g iodine/kg]) correlated with three groups using linear regressions. Correlation coefficients of ∆HU/g were 0.67 (TBW), 0.86 (LBW) and 0.85 (BSA) for the aorta, and 0.74 (TBW), 0.77 (LBW) and 0.84 (BSA) for the liver. Adjusted MHE was constant at 70.2 with LBW and at 2.69 with BSA, but correlated positively with TBW (r = 0.58, P < 0.001). Iodine load may need to be tailored by LBW or BSA in contrast enhanced MDCT of the abdomen. BSA is a simple and feasible index for the determination of iodine dose in individual patients. • Optimisation of enhancement is very important for high quality MDCT. • Iodine dose is best adjusted according to LBW or BSA. • BSA may be adopted because calculation is simple. • Iodine dose of 0.712 g/kg LBW/18.6 g/m (2) BSA gives 50 HU hepatic enhancement.

Use of the contrast volume or grams of iodine–to–creatinine clearance ratio to predict mortality after percutaneous coronary intervention

Few studies have assessed the predictive value of the ratio of the contrast media volume or grams of iodine to the creatinine clearance (V/CrCl or g-I/CrCl, respectively) for the risk of contrast-induced nephropathy (CIN) and mortality after percutaneous coronary intervention (PCI). The association between V/CrCl and mortality was prospectively evaluated in 1,135 consecutive patients undergoing PCI. Cox regression models were used to adjust for the V/CrCl ratio and other confounding factors for risk of death within 1 year. Fifty-five patients (4.84%) developed CIN. The 1-year mortality was higher in patients with a V/CrCl ratio >2.62 (g-I/CrCl >0.97) than in others (4.44% vs 0.40%; P < .001). After adjusting for other risk factors, the 1-year mortality risk remained associated with increased V/CrCl ratio. The risk of death was significant for V/CrCl >2.62 (adjusted risk ratio [RR] for death 2.605, 95% CI 1.040-6.529, P = .041), V/CrCl >3.0 (g-I/CrCl >1.11) (adjusted RR 4.338, 95% CI 1.689-11.142, P = .002), and V/CrCl >3.7 (g-I/CrCl >1.37) (adjusted RR 2.557, 95% CI 1.162-5.627, P = .002). The data further support the prognostic significance of calculating the V/CrCl ratio to predict the relative maximum contrast volume during PCI. Use of a contrast dose determined based on the estimated renal function with a planned V/CrCl ratio <3.7 (g-I/CrCl <1.37) and preferably <2.62 (g-I/CrCl <0.97) might be valuable in reducing the risks of CIN and even death after PCI.

Contrast Enhancement During Hepatic Computed Tomography

The objective of this study was to evaluate the effect of total body weight, height, body mass index, blood volume, lean body weight, and body surface area (BSA) on aortic and hepatic contrast enhancement during hepatic computed tomography (CT). We calculated the changes in the CT number per gram of iodine ((Δ Hounsfield units/g [ΔHU/g])) for the aorta and the liver during portal venous phase. We performed linear regression analyses between ΔHU/g and each of the body parameters. ΔHU/g and BSA showed the strongest inverse correlation. The correlation coefficients for the aorta and liver were 0.70 and 0.68 for ΔHU/g and total body weight, 0.41 and 0.37 for height, 0.54 and 0.55 for body mass index, 0.68 and 0.59 for blood volume, 0.70 and 0.62 for lean body weight, and 0.71 and 0.68 for BSA, respectively (P < 0.001 for all). Our study supports the use of a protocol with iodine dose adjusted for the patient BSA.

Hepatic contrast medium enhancement at computed tomography and its correlation with various body size measures

When the same dose of iodine is given to all patients when performing abdominal computed tomography (CT) there may be a wide inter-individual variation in contrast medium (CM) enhancement of the liver. To evaluate if any of the measures body height (BH), body mass index (BMI), lean body mass (LBM), ideal body weight (IBW), and body surface area (BSA) correlated better than body weight (BW) with hepatic enhancement, and to compare the enhancement when using iodixanol and iomeprol. One hundred patients referred for standard three-phase CT examination of abdomen were enrolled. Body weight and height were measured at the time of the CT examination. Forty grams of iodine (iodixanol 320 mg I/mL or iomeprol 400 mg I/mL) was injected at a rate of 1.6 g-I/s, followed by a 50 mL saline flush. The late arterial phase was determined by using a semi-automatic smart prep technique with a scan delay of 20 s. The hepatic parenchymal phase started automatically 25 s after the late arterial phase. CM concentration was estimated by placement of regions of interest in aorta (native and late arterial phase) and in liver (native and parenchymal phase). BW (r = -0.51 and -0.64), LBM (r = -0.54 and -0.59), and BSA (r = -0.54 and -0.65) showed the best correlation coefficients with aortic and hepatic parenchymal enhancement, respectively, without any significant differences between the measures. Comparing iodixanol and iomeprol there was no significant difference in aortic enhancement. The liver enhancement was significantly higher (P < 0.05) using iodixanol than iomeprol. To achieve a consistent hepatic enhancement, CM dose may simply be adjusted to body weight instead of using more complicated calculated parameters based on both weight and height.

Optimization of Contrast Material Delivery for Dual-Energy Computed Tomography Pulmonary Angiography in Patients With Suspected Pulmonary Embolism

To prospectively compare subjective and objective measures of image quality using 4 different contrast material injection protocols in dual-energy computed tomography pulmonary angiography (CTPA) studies of patients with suspected pulmonary embolism. A total of 100 consecutive patients referred for CTPA for the exclusion of pulmonary embolism were randomized into 1 of 4 contrast material injection protocols manipulating iodine concentration and iodine delivery rate (IDR, expressed as grams of iodine per second): Iomeprol 400 at 3 mL/s (IDR = 1.2 gI/s), iomeprol 400 at 4 mL/s (IDR = 1.6 gI/s), iomeprol 300 at 5.4 mL/s (IDR = 1.6 gI/s), or iomeprol 300 at 4 mL/s (IDR = 1.2 gI/s). Total iodine delivery was held constant. Dual-energy CTPA of the lungs were acquired and used to calculate virtual 120 kV CTPA images as well as iodine perfusion maps. Attenuation values in the thoracic vasculature and image quality of virtual 120 kV CTPAs were compared between groups. Iodine perfusion maps were also compared by identifying differences in the extent of beam-hardening artifacts and subjective image quality. Protocols with an IDR of 1.6 gI/s provided the best attenuation profiles. CTPA image quality was greatest in the high concentration, high IDR (1.6 gI/s) protocol (P < 0.05 for all group comparisons) with no differences between the other groups (all P ≥ 0.05). Extent of beam-hardening artifacts and perfusion map image quality was significantly better using the high concentration, high IDR protocol as compared with all groups (P < 0.05 for all comparisons) and significantly worse using the low concentration, low IDR protocol as compared with all groups (all P ≥ 0.05); no difference was found between the high concentration, low IDR protocol and the low concentration, high IDR protocol (P = 0.73 for comparison of beam-hardening artifacts; P = 0.50 for comparison of perfusion map image quality). High iodine concentration and high IDR contrast material delivery protocols provide the best image quality of both CTPA and perfusion map images of the lung through high attenuation in the pulmonary arteries and minimization of beam-hardening artifacts.

Determination of Safe Contrast Media Dosage to Estimated Glomerular Filtration Rate Ratios to Avoid Contrast-Induced Nephropathy After Elective Percutaneous Coronary Intervention

Background and ObjectivesTo avoid the risk of developing contrast-induced nephropathy (CIN), it has been suggested that patients be subjected to a minimal necessary dose of contrast medium (CM-dose). However, often it is not easy to determine such a dose. This study assessed the usefulness of the ratio of CM-dose to estimated glomerular filtration rate (eGFR) in predicting the risks of CIN and sought to determine the safe level of CM-dose/eGFR in patients undergoing non-emergent percutaneous coronary intervention (PCI).Subjects and MethodsWe enrolled a total of 226 patients and calculated the ratio of CM-dose using grams of iodine (g-I) to eGFR, thus expressing it as g-I/eGFR. Among the CIN patients, those with ne-phropathy requiring dialysis (NRD) were also evaluated.ResultsOverall, there were 16 cases (7.1%) of CIN. On univariate and multivariate regression analysis, g-I/eGFR alone was found to be an independent predictor for CIN (hazard ratio=10.73, p<0.001). In an receiver operating characteristic analysis, fair discrimination for CIN was found at a g-I/eGFR level of 1.42 (C statics=0.867), and at this value, the sensitivity and specificity were 81.3% and 80%, respectively. Of patients (n=51) with g-I/eGFR ≥1.42, 23.6% (13/51) and 7.8% (4/51) developed, while those with g-I/eGFR <1.42 (n=171) had a lower incidences of CIN (1.8%, 2/171, p<0.001) and NRD (0%, 0/171, p<0.001).ConclusionIt can be concluded that a g-I/eGFR <1.42 is a simple, useful indicator for determining the safe CM-dose based on the pre-PCI eGFR values. Furthermore, g-I/eGFR might have a close relationship with the development of NRD as well as CIN.

Body Size Indexes for Optimizing Iodine Dose for Aortic and Hepatic Enhancement at Multidetector CT: Comparison of Total Body Weight, Lean Body Weight, and Blood Volume

To evaluate and compare total body weight (TBW), lean body weight (LBW), and estimated blood volume (BV) for the adjustment of the iodine dose required for contrast material-enhanced multidetector computed tomography (CT) of the aorta and liver. Institutional review committee approval and written informed consent were obtained. One hundred twenty patients (54 men, 66 women; mean age, 64.1 years; range, 19-88 years) who underwent multidetector CT of the upper abdomen were randomized into three groups of 40 patients each: (a) TBW group (0.6 g of iodine per kilogram of TBW), (b) LBW group (0.821 g of iodine per kilogram of LBW), and (c) BV group (men, 8.6 g of iodine per liter of BV; women, 9.9 g of iodine per liter of BV). Change in CT number between unenhanced and contrast-enhanced images per gram of iodine and maximum hepatic enhancement (MHE) adjusted for iodine dose were examined for correlation with TBW, LBW, and BV by using linear regression analysis. In the portal venous phase, correlation coefficients for the correlation of change in CT number per gram of iodine with TBW for the aorta and liver were -0.71 and -0.79, respectively, in the TBW group; -0.80 and -0.86, respectively, in the LBW group; and -0.68 and -0.66, respectively, in the BV group. In the liver, they were marginally higher in the LBW group than in the BV group (P = .03). Adjusted MHE remained constant at 77.9 HU +/- 10.2 (standard deviation) in the LBW group with respect to TBW, but it increased in the TBW (r = 0.80, P < .001) and BV (r = 0.70, P < .001) groups as TBW increased. When LBW, rather than TBW or BV, is used, the iodine dose required to achieve consistent hepatic enhancement may be estimated more precisely and with reduced patient-to-patient variability.