Kinetic analysis of mass transfer of Eu(III) in extractant-impregnated polymer-layered silica particle in multiple-ion distribution system.

The Eu(III) distribution mechanism in single extractant-impregnated polymer-layered silica particle in a complex solution containing multiple lanthanide ions was investigated using fluorescence microspectroscopy, which was compared with the single-ion distribution system. The rate-determining step of the Eu(III) distribution was the reaction of Eu(III) with the two extractant molecules in the particle. The distribution mechanism and rate constants obtained in the multiple lanthanide ions-distribution system agreed with those of the single-ion distribution system.

Eu(III) transfer in single N,N,N',N'-tetraoctyldiglycolamide-impregnated polymer-coated silica particle using fluorescence microspectroscopy: transfer mechanism and effect of polymer crosslinking degree.

A microcapillary manipulation system combined with fluorescence microspectroscopy enabled us to analyze mass transfer in a single particle. In this study, we revealed the Eu(III) distribution in a single diglycolamide-derivative extractant (TODGA)-impregnated polymer-coated silica particle. The reaction of Eu(III) with two TODGA molecules in the polymer layer was the rate-limiting process, which was revealed by the relationship between the rate constants (k1 and k-1) and concentrations of Eu(III) and HNO3. The decrease in the crosslinking degree of the polymer layer caused an increase in only k-1. This indicates that hydrophilic environments at lower crosslinking degrees enhance the stability of the charged Eu(III) species such as Eu3+, Eu(NO3)2+, and Eu(NO3)2+.

Kinetics and mechanism of Eu(III) transfer in tributyl phosphate microdroplet/HNO3 aqueous solution system revealed by fluorescence microspectroscopy.

In this study, we reveal an Eu(III) extraction mechanism at the interface between HNO3 and tributyl phosphate (TBP) solutions using fluorescence microspectroscopy. The mass transfer rate constant at the interface is obtained from the analysis of fluorescence intensity changes during the forward and backward extractions at various HNO3 and TBP concentrations to investigate the reaction mechanism. This result indicates that one nitrate ion reacts with Eu(III) at the interface, whereas TBP molecules are not involved in the interfacial reaction, which is different from the results obtained using the NaNO3 solution in our previous study. We demonstrate that the chemical species of Eu(III) complex with nitrate ion and TBP in the aqueous solution play an important role for the extraction mechanism. The rate constants of the interfacial reactions in the forward and backward extractions are (4.0-5.0) × 10-7 m M-1 s-1 and (3.2-3.3) × 10-6 m s-1, respectively. We expect that our revealed mechanism provides useful and fundamental knowledge for actual solvent extraction.

Extraction Mechanism of Lanthanide Ions into Silica-based Microparticles Studied by Single Microparticle Manipulation and Microspectroscopy.

Single porous silica microparticles coated with a styrene-divinylbenzene polymer (SDB) impregnated with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) were injected into an aqueous 3 mol/L nitric acid solution containing trivalent lanthanide (Ln(III)), as a high-level liquid waste model. We used the microcapillary manipulation-injection technique; and the extraction rate of Ln(III), as an Ln(III)-CMPO complex, into the single microparticles was measured by luminescence microspectroscopy. The extraction rate significantly depended on the Ln(III), CMPO, or NO3- concentration, and was analyzed in terms of diffusion in the pores of the microparticles and the complex formation of Ln(III). The results indicated that the rate-determining step in Ln(III) extraction was diffusion in the pore solution of the microparticles.

Coronary vasodilation by the use of sublingual nitroglycerin using 64-slice dual-source coronary computed tomography angiography.

BACKGROUND: Sublingual nitroglycerin capsules or spray is routinely used to treat anginal attacks and to maximally dilate the epicardial coronary arteries during coronary angiography. These dilated coronary vessels have an advantage, but increased heart rates were disadvantageous for coronary computed tomography angiography (CTA). PURPOSE: The influence of applying nitroglycerin was analyzed regarding the coronary diameter, coronary luminal attenuation, evaluable number of coronary segments, heart rate (HR), HR variability, the optimal reconstruction phase, and image scoring of CTA in the same patients using a 64-slice dual-source CT. METHODS AND SUBJECTS: Fifty-two patients with atypical chest pain underwent coronary CTA before and after the administration of sublingual nitroglycerin without heart rate control. The coronary diameter and luminal attenuation were measured on short-axial images in each coronary segment. The coronary vasodilation ratios (VRs) were calculated from the coronary diameters at the same location before and after the use of nitroglycerin. The local institutional review board approved this study and written informed consent was obtained from all the patients. RESULTS: No significant differences were noted in the HR variability or optimal reconstruction phase, despite an increase in HR after the use of nitroglycerin. Nitroglycerin significantly enlarged the coronary artery diameter, and VRs of each coronary segment ranged from 7.54% to 22.26%. As compared with baseline coronary diameter, VRs of minor segments (16.91%) were significantly larger than those of major segments (11.35%), and the magnitude of VR correlated with the baseline coronary diameter (r=-0.48, p<0.001). Coronary luminal attenuation significantly increased due to additional administration of contrast material after the use of nitroglycerin (p<0.01), but no significant difference was noted in the image quality after the use of nitroglycerin. CONCLUSION: Sublingual nitroglycerin significantly enlarged the coronary diameters, especially in peripheral small coronary arteries, and increased the evaluable number of coronary segments on coronary CTA.

Volumetric evaluation of dual-energy perfusion CT by the presence of intrapulmonary clots using a 64-slice dual-source CT.

BACKGROUND: Dual-energy perfusion CT (DEpCT) directly represents the iodine distribution in lung parenchyma and low perfusion areas caused by intrapulmonary clots (IPCs) are visualized as low attenuation areas. PURPOSE: To evaluate if volumetric evaluation of DEpCT can be used as a predictor of right heart strain by the presence of IPCs. MATERIAL AND METHODS: One hundred and ninety-six patients suspected of having acute pulmonary embolism (PE) underwent DEpCT using a 64-slice dual-source CT. DEpCT images were three-dimensionally reconstructed with four threshold ranges: 1-120 HU (V120), 1-15 HU (V15), 1-10 HU (V10), and 1-5 HU (V5). Each relative ratio per V120 was expressed as the %V15, %V10, and %V5. Volumetric data-sets were compared with D-dimer, pulmonary arterial (PA) pressure, right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio, PA diameter, and PA/aorta (PA/Ao) diameter ratio. The areas under the ROC curves (AUCs) were examined for their relationship to the presence of IPCs. This study was approved by the local ethics committee. RESULTS: PA pressure and D-dimer were significantly higher in the patients who had IPCs. In the patients with IPCs, V15, V10, V5, %V15, %V10, and %V5 were also significantly higher than those without IPC (P ≤ 0.001). %V5 had a better correlation with D-dimer (r = 0.30, P < 0.001) and RV/LV diameter ratio (r = 0.27, P < 0.001), and showed a higher AUC (0.73) than the other CT measurements. CONCLUSION: The volumetric evaluation by DEpCT had a correlation with D-dimer and RV/LV diameter ratio, and the relative ratio of volumetric CT measurements with a lower attenuation threshold might be recommended for the analysis of acute PE.

Dual-energy perfusion CT of non-diseased lung segments using dual-source CT: correlation with perfusion SPECT.

PURPOSE: To determine the utility of dual-energy perfusion CT (DEpCT) of non-diseased lung segments, using dual-source CT, in comparison with perfusion single-photon emission computed tomography (SPECT). MATERIALS AND METHODS: 28 patients (18 male and 10 female; mean age 63 years; age range 18-86 years) underwent DEpCT and SPECT within a 3-day interval. The presence and location of perfusion defects in each segment of the lungs were evaluated. RESULTS: Perfusion defects were noted in 7 of 361 segments (1.9%) by DEpCT and in 19 of 361 segments (5.3%) by perfusion SPECT. DEpCT was in good agreement with perfusion SPECT for 338 of 361 segments (93.6%). Intraobserver agreement was also good, ranging from 93.4 to 93.6% (κ = 0.64-0.75, p < 0.01). CONCLUSION: For non-diseased lung segments, DEpCT correlated well with SPECT.

Comparison of lumbar drainage and external ventricular drainage for clearance of subarachnoid clots after Guglielmi detachable coil embolization for aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Subarachnoid clots play an important role in development of delayed vasospasm after subarachnoid hemorrhage (SAH). The purpose of this study was to compare clearance of subarachnoid clots using external ventricular drainage (EVD) or lumbar drainage (LD) after Guglielmi detachable coil (GDC) embolization for aneurysmal SAH. METHODS: The subjects were 51 treated with GDC coil embolization for aneurysmal Fisher group 3 SAH within 72 h of ictus. Software-based volumetric quantification of the subarachnoid clots was performed on CT scans and the hemoglobin (Hb) level was measured in CSF drained from each catheter. RESULTS: Clearance of subarachnoid clots was more rapid in patients treated with LD (n=34) compared to those treated with EVD (n=17). The Hb level in CSF was significantly higher in the LD group on Days 4-5 after onset of SAH (P<0.05), but was higher in the EVD group on Days 8-9. The incidence of symptomatic vasospasm did not differ between the two groups. The rate of occurrence of a new low density area on CT scans was higher in patients treated with EVD, but not significantly higher than the rate in the LD group. CONCLUSION: GDC embolization followed by lumbar drainage accelerates the reduction of subarachnoid clots, but EVD may contribute to stasis of hemorrhage within subarachnoid spaces.

The low attenuation area on dual-energy perfusion CT: correlation with the pulmonary function tests and quantitative CT measurements.

PURPOSE: To retrospectively investigate the distribution of the low attenuation area (LAA) on dual energy perfusion CT (DEpCT) in comparison with the results of pulmonary function tests (PFTs) and quantitative CT measurements. MATERIALS AND METHODS: Twenty-eight patients (15 male and 13 female; mean age: 62.21 years) underwent DEpCT and PFTs within a 1-month interval. The ranges of the LAA on DEpCT were classified into six groups with attenuation values of 0-3, 0-5, 0-8, 0-10, 0-13 and 0-15 HU and the ratios of LAA in each group were compared with the percentage of forced expiratory volume in the 1st second (%FEV(1.0)), FEV(1.0)/forced vital capacity (FEV(1.0)/FVC) and the relative area of the lung with attenuation coefficients lower than -950 HU (RA(-950)). RESULTS: The LAAs on the DEpCT images were significantly correlated with the RA(-950), %FEV(1.0) and FEV(1.0)/FVC, and the regression analysis showed that the best values of LAA on DEpCT were 0-10 HU with RA(-950) (r=0.63), 0-8 HU with %FEV(1.0) (r=-0.52) and 0-8HU with FEV(1.0)/FVC (r=-0.61) per patient. CONCLUSION: The iodine disturbance on DEpCT had a moderate correlation with the results of the PFTs and RA(-950), but further examination would be needed for evaluation of iodine distribution.

Systolic reconstruction in patients with low heart rate using coronary dual-source CT angiography.

OBJECTIVES: The purpose of our study was to determine the relationship between the predictive factors and systolic reconstruction (SR) as an optimal reconstruction window in patients with low heart rate (LHR; less than 65 bpm). METHODS: 391 patients (262 male and 129 female, mean age; 67.1±10.1 years of age) underwent coronary CTA without the additional administration of a beta-blocker. Affecting factors for SR were analyzed in age, gender, body weight (BW), diabetes mellitus (DM), coronary arterial disease (CAD), ejection fraction (EF), systolic and diastolic body pressure (BP) and heart rate variability (HRV) during coronary CTA. RESULTS: In 29 (7.4%) of the 391 patients, SR was needed, but there was no apparent characteristic difference between the systolic and diastolic reconstruction groups in terms of gender, age, BW, DM, CAD and EF. In a multivariate analysis, the co-existence of DM [P<0.05; OR, 0.27; 95% CI, 0.092-0.80], diastolic BP [P<0.01; OR, 0.95; 95% CI, 0.92-0.98] and HRV [P<0.01; OR, 0.98; 95% CI, 0.96-0.99] were found to be the factors for SR. In gender-related analysis, HRV was an important factor regardless of sex, but co-existence of DM affected especially for female and BP for male. CONCLUSION: Especially in the patients with LHR who had a medication of DM, high HRV or high BP, SR, in addition to DR, was needed to obtain high-quality coronary CTA images.

Fate of clots in patients with subarachnoid hemorrhage after different surgical treatment modality: a comparison between surgical clipping and Guglielmi detachable coil embolization.

BACKGROUND: Subarachnoid clot is important in the development of delayed vasospasm after subarachnoid hemorrhage (SAH). OBJECTIVE: To compare the clearance of subarachnoid clot and the incidence of symptomatic vasospasm in surgical clipping and embolization with Guglielmi detachable coils for aneurysmal SAH. METHODS: The subjects were 115 patients with Fisher group 3 aneurysmal SAH on computed tomography scan at admission whose aneurysm was treated by surgical clipping (clip group; n = 86) or Guglielmi detachable coil embolization (coil group; n = 29) within 72 hours of ictus. Software-based volumetric quantification of the subarachnoid clot was performed, and the amount of hemoglobin in drained cerebrospinal fluid was measured. RESULTS: Clearance of the subarachnoid clot on the computed tomography scan was rapid in the clip group until the day after the operation but slow in the coil group (58.9% removed vs 27.8% removed; P = .008). However, postoperative clearance of the clot occurred more rapidly in the coil group. Reduction of the clot until days 3 through 5 did not differ significantly between the 2 groups (72.9% removed vs 75.2% removed). The amount of hemoglobin in the clip group was > 0.8 g/d until day 3 and then gradually decreased (n = 15), but hemoglobin in the coil group remained at > 0.8 g/d until day 5 (n = 17). The incidence of symptomatic vasospasm did not differ between the groups. CONCLUSION: Subarachnoid clot can be removed directly during surgical clipping, which is not possible with endovascular treatment. However, the percentage reduction of the clot on days 3 through 5 did not differ between the 2 groups.

[Study of image quality (contrast) and reduction of patient dose by using heavy metal filters].

We studied image quality (contrast) and patient dose reduction using heavy metal filters in lumbar spine and abdomen x-ray examination. Heavy metal filters used in this study are gadolinium, holmium and ytterbium and these combinations. These filters have k-absorption edge in the range from 50 to 70 keV. Image quality and patient dose in 70-90 kV tube voltage with heavy metal filters were compared with 80 kV tube voltage without filter. Image quality was improved in four percent and patient dose could be reduced by 30%. However, tube loading increased from 1.6 to 2.2 times. It was found that the best filter choices gave better image and reduced patient dose compared to without filter.