Minimizing individual variations in arterial enhancement on coronary CT angiographs using "contrast enhancement optimizer": a prospective randomized single-center study.

OBJECTIVES: To investigate the clinical utility of our newly developed contrast enhancement optimizer (CEO) software for coronary CT angiography (CCTA). METHODS: We randomly assigned 295 patients (168 males, 127 females, median age 71 years) undergoing CCTA to one of two contrast media injection protocols. Group A (n = 150) was injected with a CEO-selected iodine dose based on patient factors. In group B (n = 145), we used our standard protocol (245 mg I/kg). We recorded the CT number in the ascending aorta and determined whether the CT number was equivalent in groups A and B. For the equivalence test, we adopted 75 Hounsfield units (HU) as the equivalence margin. The standard deviation in the CT number and the rate of patients with an acceptable CT number were compared using the F test and the chi-square test, respectively. RESULTS: The iodine dose in group A was significantly smaller than that in group B (235.7 vs. 253.6 mg I/kg, p < 0.001). The CT number of the ascending aorta was 428.6 ± 55.5 HU in group A and 436.1 ± 68.7 HU in group B; the 95% confidence interval for the difference between the groups was -4.3 HU to 16.9 HU and within the range of the predetermined equivalence margins. In group A, the variance was significantly smaller than that in group B (p = 0.009). The number of patients with an acceptable CT number was significantly higher in group A than in group B (84.7% vs. 71.7%, p = 0.007). CONCLUSIONS: The use of our CEO for CCTA studies yielded optimal aortic contrast enhancement in significantly more patients than the standard protocol based on the body weight. KEY POINTS: • With our contrast enhancement optimizer (CEO) software, optimal and stable aortic enhancement can be obtained on coronary CT angiography scans irrespective of patient factors. • Management of contrast media becomes more appropriate by the CEO software. • The CEO software can control contrast enhancement at different tube voltage levels.

Late iodine enhancement computed tomography with image subtraction for assessment of myocardial infarction.

OBJECTIVE: To evaluate the feasibility of image subtraction in late iodine enhancement CT (LIE-CT) for assessment of myocardial infarction (MI). METHODS: A comprehensive cardiac CT protocol and late gadolinium enhancement MRI (LGE-MRI) was used to assess coronary artery disease in 27 patients. LIE-CT was performed after stress CT perfusion (CTP) and CT angiography. Subtraction LIE-CT was created by subtracting the mask volume of the left ventricle (LV) cavity from the original LIE-CT using CTP dataset. The %MI volume was quantified as the ratio of LIE to entire LV volume, and transmural extent (TME) of LIE was classified as 0%, 1-24%, 25-49%, 50-74% or 75-100%. These results were compared with LGE-MRI using the Spearman rank test, Bland-Altman method and chi-square test. RESULTS: One hundred twenty-five (29%) of 432 segments were positive on LGE-MRI. Correlation coefficients for original and subtraction LIE-CT to LGE-MRI were 0.79 and 0.85 for %MI volume. Concordances of the 5-point grading scale between original and subtraction LIE-CT with LGE-MRI were 75% and 84% for TME; concordance was significantly improved using the subtraction technique (p <0.05). CONCLUSION: Subtraction LIE-CT allowed more accurate assessment of MI extent than the original LIE-CT. KEY POINTS: • Subtraction LIE-CT allows for accurate assessment of the extent of myocardial infarction. • Subtraction LIE-CT shows a close correlation with LGE-MRI in %MI volume. • Subtraction LIE-CT has significantly higher concordance with TME assessment than original LIE-CT.

Differential activation of signaling pathways by low-osmolar and iso-osmolar radiocontrast agents in human renal tubular cells.

Radiocontrast media (RCM)-induced nephrotoxicity (CIN) is a major clinical problem accounting for 12% of all hospital-acquired cases of acute kidney injury (AKI). The pathophysiology of AKI due to RCM is not well understood, but direct toxic effects on renal cells have been postulated as contributing to CIN. It is believed that iso-osmolar RCM (IOCM) are less nephrotoxic than low-osmolar RCM (LOCM) but clinical data have been controversial. We have investigated the intracellular signaling pathways that may be affected by the LOCM iomeprol (IOM) and the IOCM iodixanol (IOD). Both IOM and IOD caused a dramatic decrease in phosphorylation of the kinase Akt at Ser473 and Thr308 in human renal tubular (HK-2) cells, with IOM having a greater effect; IOM also caused a greater decrease in cell viability. IOM also had a greater effect on phosphorylation of p38 MAP kinases, JNKs, and NF-kB (Ser276), and caused a marked decrease in the phosphorylation of forkhead box O3a (FOXO3a) and signal transducer and activator of transcription 3 (STAT3). However, IOD caused a greater decrease in the phosphorylation of mTOR (Ser2448) and phospho-ERK 1/2 while both RCM caused a similar decrease in the phosphorylation of phospho-p70S6 kinase (Ser371). In vivo studies showed that both IOM and IOD caused a significant decrease in both pAkt (Ser473) and pERK 1/2 in rat kidneys. Our study gives an insight into the possible mechanism of toxicity of RCM via their action on intracellular signaling pathways and may help in developing pharmacological interventions for their side-effects.

Imaging of contrast medium extravasation in anticoagulation-associated intracerebral hemorrhage with dual-energy computed tomography.

BACKGROUND AND PURPOSE: Contrast medium extravasation (CE) in intracerebral hemorrhage (ICH) is a marker of ongoing bleeding and a predictor of hematoma expansion. The aims of the study were to establish an ICH model in which CE can be quantified, characterized in ICH during warfarin and dabigatran anticoagulation, and to evaluate effects of prothrombin complex concentrates on CE in warfarin-associated ICH. METHODS: CD1-mice were pretreated orally with warfarin, dabigatran, or vehicle. Prothrombin complex concentrates were administered in a subgroup of warfarin-treated mice. ICH was induced by stereotactic injection of collagenase VIIs into the right striatum. Contrast agent (350 µL Isovue 370 mg/mL) was injected intravenously after ICH induction (2-3.5 hours). Thirty minutes later, mice were euthanized, and CE was measured by quantifying the iodine content in the hematoma using dual-energy computed tomography. RESULTS: The optimal time point for contrast injection was found to be 3 hours after ICH induction, allowing detection of both an increase and a decrease of CE using dual-energy computed tomography. CE was higher in the warfarin group compared with the controls (P=0.002). There was no significant difference in CE between dabigatran-treated mice and controls. CE was higher in the sham-treated warfarin group than in the prothrombin complex concentrates-treated warfarin group (P<0.001). CONCLUSIONS: Dual-energy computed tomography allows quantifying CE, as a marker of ongoing bleeding, in a model of anticoagulation-associated ICH. Dabigatran induces less CE in ICH than warfarin and consequently reduces risks of hematoma expansion. This constitutes a potential safety advantage of dabigatran over warfarin. Nevertheless, in case of warfarin anticoagulation, prothrombin complex concentrates reduce this side effect.

High dose intracoronary N-acetylcysteine in a porcine model of ST-elevation myocardial infarction.

We sought to evaluate the safety and efficacy of N-acetylcysteine (NAC) on ischemia and reperfusion in a pig model focusing on cardio-renal protection. High doses of NAC may provide protection from contrast induced nephropathy (CIN). NAC has also been demonstrated to reduce myocardial infarction size and improve left ventricular function after ischemia in both humans and animals studies. In this study we tested the safety and cardiorenal protective efficacy of intracoronary NAC delivered in the radiographic contrast agent in a pig model that simulates the catheter based reperfusion therapy of ST elevation myocardial infarctions. 27 pigs underwent 45 min of ischemia after surgical ligation of distal left descending coronary artery. With coronary reperfusion the animals received at total of 200 mL of the contrast agent Iopamidol with and without NAC to mimic radiographic contrast use during invasive reperfusion therapy. At 24 h the following endpoints were compared: LV function (MRI, echocardiography), myocardial injury (infarct size, area-at-risk, troponin, creatinine kinase) and CIN (creatinine, BUN and renal histology). The effects of NAC on platelet reactivity were also evaluated. Intracoronary administration of NAC administered in the contrast agent is safe. NAC reduces platelet reactivity and there was a trend towards a better cardiac function at 24 h. There was no significant difference in the size of the myocardial infarction. In this model of ischemia-reperfusion high dose NAC did not protect from CIN. High dose intracoronary NAC administered with the radiographic contrast is safe but does not provide significant cardio-renal protection.

Comparison of the effect of low- and iso-osmolar contrast agents on heart rate during chest CT angiography: results of a prospective randomized multicenter study.

PURPOSE: To prospectively compare the effect of intravenous injection of low-osmolar iopamidol with that of intravenous injection of iso-osmolar iodixanol on heart rate (HR) during nongated chest computed tomographic (CT) angiography. MATERIALS AND METHODS: This multicenter study was approved by local institutional review boards, and patients provided written informed consent. Patient enrollment and examination at centers in the United States complied with HIPAA regulations. One hundred and thirty patients (54 male; mean age, 52 years) clinically suspected of having pulmonary embolism were referred for pulmonary CT angiography and were randomly assigned to receive 80 mL of either iopamidol (370 mg of iodine per milliliter, n = 63) or iodixanol (320 mg of iodine per milliliter, n = 67) at a rate of 4 mL/sec. HR (measured in beats per minute) was monitored from 5 minutes before the start of injection to the end of imaging, and precontrast HR and maximum postcontrast HR were recorded. Student t and χ(2) tests were used for continuous and categorical variables, respectively. RESULTS: Precontrast HR in patients who received iopamidol (mean, 81 beats per minute ± 18 [standard deviation]) was similar to that in patients who received iodixanol (mean, 77 beats per minute ± 17) (P = .16). Mean postcontrast HR was 87 beats per minute ± 17 and 82 beats per minute ± 18 (P = .16) in the iopamidol and iodixanol groups, respectively. Mean increase from precontrast HR to postcontrast HR was 5 beats per minute ± 9 and 5 beats per minute ± 7 (P = .72) in the iopamidol and iodixanol groups, respectively. Thirty-five (56%) of the 63 patients who received iopamidol and 33 (49%) of the 67 patients who received iodixanol had an HR increase of fewer than 5 beats per minute, 15 (24%) and 18 (27%) patients, respectively, had an increase of 5-9 beats per minute, and four (6%) and three (4%) patients, respectively, had an increase of more than 20 beats per minute. These proportions were not significantly different between the groups (P = .51, χ(2) test). CONCLUSION: High-rate intravenous administration of 80 mL of iopamidol and iodixanol during pulmonary CT angiography slightly increased HR; there was no difference in HR between the contrast agent groups.

Liposomes coloaded with iopamidol/lipiodol as a RES-targeted contrast agent for computed tomography imaging.

PURPOSE: The need for computed tomography (CT) of reticuloendothelial system (RES)-rich organs such as the liver is increasing, particularly in patients with suspected hepatic metastasis. CT images of the liver have been improved by encapsulating currently used, water-soluble iodine contrast agent in liposomes. The present study was performed to investigate a possibility to overcome the limitations of entrapped iodine in liposomes by preparing liposomes co-loaded with iopamidol, a water-soluble iodinated compound, and lipiodol, an iodized oil. METHODS: Iopamidol and lipiodol were simultaneously loaded in liposomes by modified reverse-phase evaporation method. The entrapped iodine concentration, mean particle size and polydispersity index of resulting liposomes were evaluated. Following intravenous injection of these liposomes into rats, CT scanning was performed. RESULTS: Simultaneous loading of iopamidol and lipiodol into liposomes resulted in entrapped iodine concentrations as high as 49.2 iodine mg/ml. The mean particle size was 280 nm, and the mean polydispersity index was 0.230. CT scanning with these iopamidol/lipiodol (I/L) liposomes into rats resulted in more pronounced and more persistent increases in RES-rich organs, liver and spleen, compared with free liposomes or liposomes loaded with iopamidol alone. CONCLUSIONS: These findings indicate that I/L liposomes have the potential to allow thorough CT examination of RES-rich organs.

Me2SO perfusion time for whole-organ cryopreservation can be shortened: Results of micro-computed tomography monitoring during Me2SO perfusion of rat hearts.

Cryopreservation of whole organs and specific tissues is an important and continually expanding field of medicine. The protocols currently used for organ preservation do not ensure survivability and functionality; the protocols for ovarian tissue lead to acceptable outcomes, but these are still capable of further improvement. In general, cryopreservation protocols need to be optimized. One important approach to improving cryopreservation protocols in general involves reducing exposure to cytotoxic cryoprotective agents prior to freezing. This study, therefore, evaluated the real-time tissue penetration of dimethyl sulfoxide, a cryoprotective agent that is widely used in cryopreservation. Dimethyl sulfoxide penetration in rat hearts perfused with a 15% (v/v) dimethyl sulfoxide solution was examined in real-time using dynamic contrast-enhanced micro-computed tomography imaging. Viability of cardiomyocytes was not significantly affected by the dimethyl sulfoxide perfusion procedure. Two different perfusion rates were evaluated and compared with perfusion using a common iodine-based contrast agent (iomeprol). The dynamic contrast-enhanced micro-computed tomography imaging data showed that dimethyl sulfoxide flushes both the extracellular and intracellular spaces in rat heart tissue to 95% equilibration after ≈ 35 s via perfusion. Subsequent wash-out via perfusion is completed to 95% within ≈ 49 s. The equilibration duration routinely used in dimethyl sulfoxide-based protocols for cryopreservation should therefore be questioned. Shorter incubation duration would perhaps be sufficient, as well as being beneficial in relation to cell survivability. It would be helpful to have techniques for non-invasive real-time monitoring of the penetration of cryoprotective agents and such techniques should be used to revise cryopreservation protocols. Switching to perfusion-based equilibration procedures might be beneficial, if feasible.

Assessment of renal vasoconstriction in vivo after intra-arterial administration of the isosmotic contrast medium iodixanol compared to the low-osmotic contrast medium iopamidol.

BACKGROUND: Low-osmotic contrast media (LOCM) such as iopamidol are known to increase the renal resistance index (RRI). The aim of our study was to evaluate in vivo the different effects of intra-arterial administration of LOCM in comparison to isosmotic contrast medium (IOCM) such as iodixanol on the human RRI. METHODS: Twenty patients (16 males, 4 females; 66 years on average) with normal renal function (mean creatinine 1.0 mg/dl) had digital subtraction angiography (DSA) of the abdominal and lower-limb arteries. Ten patients received LOCM, and 10 patients IOCM (150 ml on average, 20 ml/s). The RRI was assessed by an experienced nephrologist with duplex ultrasound from 15 min before until 30 min after the first injection with delays of 1-5 min. The basic value of the RRI and differential RRI were calculated. RESULTS: The basic value of the RRI was 0.69 in the LOCM group and 0.71 in the IOCM group. After LOCM a significant increase of the RRI to 0.73 on average (P < or = 0.001) 2 min after the first injection was found, whereas IOCM did not result in a significant change of the RRI (RRI remained 0.71 on average, P > or = 0.1). In the LOCM group, the RRI returned to the basic value after 30 min (+/-2.3 min). CONCLUSIONS: Intra-arterial administration of IOCM had no influence on renal vascular resistance as expressed by the RRI, unlike LOCM, which induced a highly significant increase of the RRI for up to 30 min.

Risk of contrast-medium-induced nephropathy in high-risk patients undergoing MDCT--a pooled analysis of two randomized trials.

The incidence of contrast-medium-induced nephropathy (CIN) following intravenous (IV) CM administration of contrast media to renally impaired patients undergoing multidetector computed tomography (MDCT) is not well characterized. Our objective was to investigate the incidence of CIN in patients with glomerular filtration rate (GFR) <60 ml/min undergoing contrast-enhanced MDCT examinations and to compare the rates of CIN following the IV administration of low-osmolar contrast media (LOCM, iopamidol and iomeprol) and an iso-osmolar contrast medium (IOCM, iodixanol). A total of 301 adult patients with moderate-to-severe renal failure received a similar IV contrast dose (40 gI). Serum creatinine (SCr) was measured at screening, baseline and 48-72 +/- 6 h after the MDCT examination. Primary CIN outcome was an increase in SCr >or=0.5 mg/dl (>or=44.2 micromol/l) from baseline. The CIN rates were 2.3% in the total population, 0.6% when GFR >40 ml/min, 4.6% when GFR <40 ml/min and 7.8% in patients with GFR <30 ml/min. The incidence of CIN was significantly higher after iodixanol than after LOCM (seven patients, 4.7% following IOCM, no CIN cases following the LOCM; p = 0.007). Significant differences in favor of the LOCM were also observed in patients with GFR <40 ml/min and GFR <30 ml/min. Following the IV administration of nonionic contrast agents in patients with moderate-to-severe renal insufficiency, the risk of significant CIN seems to be low. The IOCM iodixanol caused a higher rate of CIN than the LOCM iopamidol and iomeprol, especially in high-risk patients. Differences in osmolality between these LOCM and iodixanol do not play a role in the genesis of CIN.

Influence of various radiographic contrast media on the buckling of endothelial cells.

The intra-arterial application of radiographic contrast media (RCM) can induce decreases of blood flow velocity in downstream capillaries as well as a decrease in the tissue oxygen tension. It is unclear whether changes in endothelial cell morphology contribute to the observed microcirculatory disorders. Four RCMs (Iodixanol320, Iohexol350, Iopromide370, and Imeron350) were added to the culture medium of human umbilical venous endothelial cells (HUVEC) and used for short-term incubation studies of these cells. Addition of Iohexol (p=0.6377) and Iodixanol (p=0.6309) did not affect the HUVEC height 1.5 min after incubation in the modified cell culture media supplemented with 30% v/v of the respective RCM. Strong buckling and increased endothelial height appeared after incubation in Iopromide-supplemented medium (the cell height increased by 95% compared to cells incubated under control conditions; p=0.0065). Addition of Iomeprol-supplemented medium caused an increase by 61.6% compared to cells incubated under control conditions; p=0.0051. After 5 min of incubation in any of the RCM-supplemented media, there was no difference in HUVEC height in comparison to incubation in control standard culture media (each p value>0.05). The tremendous buckling caused by Iopromide and Iomeprol, coinciding with an echinocyte formation of erythrocytes might be the reason why a bolus injection of Iopromide in vivo into the left coronary artery was followed by a 50% decrease of oxygen partial pressure in the supplied tissue.

Iodinated contrast media: effect of osmolarity and injection temperature on erythrocyte morphology in vitro.

BACKGROUND: Some side effects of intravenously injected iodinated contrast media are thought to be linked to the biological properties of the various agents and their effect on blood components. PURPOSE: To assess the effect of osmolarity and injection temperature of iodinated contrast media on erythrocyte (RBC) morphology in vitro. MATERIAL AND METHODS: Blood from 20 volunteers was incubated with three different contrast media (320 mg I/ml iso-osmolar iodixanol, 300 mg I/ml low-osmolar iopromide, 300 mg I/ml low-osmolar iopamidol) injected at 37 degrees C, 43 degrees C, and 48 degrees C, and in two different volumes corresponding to the estimated concentration at the site of venous injection and after systemic distribution. After 10 min incubation, aliquots were removed for complete blood count analysis and blood smears. Two hematologists blindedly and independently reviewed all smears, and determined the grade of morphological RBC changes compared to a blank sample. RESULTS: There was excellent (kappa = 0.98) inter-reader correlation for grading RBC changes. At systemic concentration at 37 degrees C, the grade of RBC changes was significantly (P<0.05) less in blood samples exposed to iso-osmolar iodixanol (mean 0.21) as compared to low-osmolar iopromide (mean 0.26) and low-osmolar iopamidol (mean 0.58). These differences became more significant at higher volumes, corresponding to concentrations at the site of injection and higher injection temperatures. CONCLUSION: In vitro, RBC morphology is less affected by iso-osmolar as compared to low-osmolar contrast media. These differences become more significant at higher injection temperatures that are proposed to improve flow dynamics for high-speed injection.

Reversibility of echinocyte formation after contact of erythrocytes with various radiographic contrast media.

Various radiographic contrast media (RCM) significantly influence the morphology of erythrocytes, especially the formation of echinocytes [Scand. J. Clin. Lab. Invest. 35 (1975), 1-43; Microvasc. Res. 60 (2000), 193-200; Herz 23 (2003), 35-41]. Microscopic studies, however, have shown that these changes of erythrocyte morphology are possibly reversible [Acta Radiol. 37 (1996), 214-217]. The aim of this study was to proof if the RCM-induced echinocyte formation can be reversed by a resuspension in autologous plasma. In this study four RCMs were tested (Iodixanol, Iohexol, Iomeprol and Iopromide). These RCM induced echinocyte formation (after suspension of erythrocytes in plasma/RCM mixtures for 10 min at 37 degrees C), which was reversible after resuspension in autologous RCM-free plasma (resuspension time 5 min at 37 degrees C). Especially for Iomeprol and Iopromide - the RCMs which induced the strongest echinocyte formation - an echinocyte reduction from 94.2% to 44.5% and for Iopromide from 80.6% to 50.4% occurred. The echinocyte formation was influenced by the type of RCM as well as by the RCM concentration. The same was true for the reversibility of echinocyte formation due to resuspension in autologous plasma (type of RCM: p

Quantitative assessment of blood volume, blood flow, and permeability of the brain of clinically normal dogs by use of dynamic contrast-enhanced computed tomography.

OBJECTIVE: To determine effects of regional variation, interobserver variability, and vessel selection on quantitative vascular variables derived by dynamic contrast-enhanced computed tomography (DCE-CT) of the brain of clinically normal dogs. ANIMALS: 14 adult dogs with no evidence of CNS dysfunction. PROCEDURES: Dogs were randomly assigned to 4 groups, and DCE-CT was performed at the level of the frontal lobe, rostral portion of the parietal-temporal lobes, caudal portions of the parietal-temporal lobes, or occipital lobe-cerebellum for groups 1 to 4, respectively. Cerebral blood flow (CBF), cerebral blood volume (CBV), and permeability in gray and white matter for both a large and small artery were calculated and compared. Values among 3 observers and 4 regions of the brain were calculated and compared. RESULTS: Significant interobserver variability was detected for CBF and permeability in white matter. Values calculated for large and small arteries were correlated for CBV and CBF but not for permeability. Overall mean +/- SD for CBF, CBV, and permeability in gray matter was 53.5 +/- 27.7 mL/min/100 g, 2.9 +/- 1.4 mL/100 g, and 1.4 +/- 2.2 mL/min/100 g, respectively. Mean for CBF, CBV, and permeability in white matter was 44.2 +/- 28.5 mL/min/100 g, 2.5 +/- 1.5 mL/100 g, and 0.9 +/- 0.7 mL/min/100 g, respectively. Values did not differ significantly among brain regions. CONCLUSIONS AND CLINICAL RELEVANCE: Significant regional variations were not detected for quantitative vascular variables in the brain of clinically normal dogs. However, interobserver variability and vessel selection have an important role in variable estimation.

Hemodynamic effects of monomeric nonionic contrast media in pulmonary angiography in chronic thromboembolic pulmonary hypertension.

OBJECTIVE: The purpose of this study was to investigate the hemodynamic safety of the monomeric nonionic contrast agent iomeprol for selective pulmonary angiography in chronic thromboembolic pulmonary hypertension (CTPH), and to investigate the effect of periinterventional oxygen administration. SUBJECTS AND METHODS: Selective pulmonary digital subtraction angiography was performed in 94 patients with CTPH using six bolus injections of iomeprol (posteroanterior, oblique, and lateral projections; both pulmonary arteries; iomeprol, 25 mL at 13 mL/s). Hemodynamics were obtained with Swan-Ganz catheters, and systolic pulmonary artery pressure (PAsyst) was classified into one of three groups: 30 mm Hg or less (control group), greater than 30 but less than or equal to 60 mm Hg (group 1, moderate pulmonary hypertension), and greater than 60 mm Hg (group 2, severe pulmonary hypertension). RESULTS: At baseline, values for PAsyst were 21.4 +/- 2.3 (control group, n = 8), 49.8+/- 8.5 (group 1, n = 18), and 86.5 +/- 18.9 (group 2, n = 68) mm Hg (p < 0.001). Pulmonary vascular resistance indexes (PVRI) were 222 +/- 105 (control), 703 +/- 364 (group 1), and 1,582 +/- 562 (group 2) dyne x s x cm(-5) x m2 (p < 0.001). The mean cardiac indexes were 3.1 (control), 2.8 (group 1), and 2.3 (group 2) L/min/m2 (p < 0.05). Pulmonary capillary wedge pressure (PCw) indicated healthy left heart function. Periinterventional oxygen inhalation improved oxygen saturation in all groups and slightly reduced pulmonary artery pressure and heart rate. Online measurement of pulmonary artery pressure during contrast bolus injection for angiography showed only a minor increase, predominantly in severe pulmonary hypertension (triangle up [difference] PAsyst: 1.3 +/- 1.9 [control], 2.9 +/- 3.4 [group 1], and 3.8 +/- 4.5 [group 2] mm Hg [p < 0.001]). After completion of angiography, right atrial pressure (RAP) and PAsyst were moderately increased: triangle up RAP: 1.4 (control), 2.6 (group 1, p < 0.001), and 3.0 (group 2, p < 0.001) mm Hg; triangle up PAsyst: 3.2 (control), 7.7 (group 1, p < 0.01), and 8.5 (group 2) mm Hg (p < 0.001). PVRI was significantly higher in group 2 (triangle up PVRI: 188 dyne x s x cm(-5) x m2, p < 0.001). CONCLUSION: Selective pulmonary angiography using iomeprol is safe without critical pressure peaks during selective contrast bolus injection or significant hemodynamic derangement in severe CTPH. Periinterventional oxygen inhalation improved pulmonary circulation.

Factors contributing to blood-brain barrier disruption following intracarotid injection of nonionic iodinated contrast medium for cerebral angiography: experimental study in rabbits.

PURPOSE: This study was performed to investigate the role of injection methods and conditions under a fixed dose of radiographic contrast medium (CM) in respect to promoting blood-brain barrier (BBB) disruption. MATERIALS AND METHODS: A total of 44 white rabbits (average body weight 2.7 +/- 0.4 kg) were used, and their carotid injection was performed with nonionic CM. The variables assessed for the carotid injections included the following: iodine content (300 or 150 mg I/ml), liquid temperature (37 degrees or 24 degrees C), and the injection time duration (1 or 30 s). The rabbits were divided into five groups. To evaluate BBB disruption, pre- and post-contrast-enhanced magnetic resonance (MR) studies were performed. RESULTS: Abnormal enhancement of the brain parenchyma in MRI was noted in only one group, which consisted of high-iodine concentration CM injected at a low temperature over a short injection interval. Statistically significant increased values for the percentage of relative enhancement (RE%) were demonstrated (P < 0.05) in comparison with the saline-injected control group. CONCLUSION: This result suggests variables that may need to be carefully considered to prevent BBB injury induced by nonionic CM for cerebral angiography, especially in the setting of a neurointerventional procedure.

Cardiac helical CT involving a low-radiation-dose protocol with a 100-kVp setting: Usefulness of hybrid iterative reconstruction and display preset optimization.

To compare the radiation dose and image quality of retrospective electrocardiogram (ECG)-gated cardiac computed tomography (CT) between a 100-kVp protocol, hybrid iterative reconstruction (HIR), and display preset optimization and the 120-kVp protocol.We prospectively enrolled 100 patients with tachycardia or atrial fibrillation scanned retrospective ECG-gated cardiac CT. We randomly assigned 50 patients to the 120-kVp protocol and 50 patients to the 100-kVp protocol. We compared effective doses (EDs) between the two protocols. The 120-kVp images were post-processed using filtered back projection (FBP). The 100-kVp images were post-processed using FBP (100-kVp protocol) and HIR (i-100-kVp protocol). We compared attenuation of the ascending aorta, signal-to-noise ratio (SNR), and image noise between the 120-kVp, 100-kVp, and i-100-kVp protocols. We performed qualitative image analysis for the 120-kVp and i-100-kVp protocols.ED of the 100-kVp protocol (4.4 ±â€Š0.4 mSv) was 76% lower than that of the 120-kVp protocol (18.4 ±â€Š0.6 mSv). Attenuations of the 100-kVp (549.1 ±â€Š73.8 HU) and i-100-kVp (550.5 ±â€Š73.7 HU) protocols were higher than that of the120-kVp protocol (437.3 ±â€Š55.7 HU). Image noise of the 100-kVp (53.6 ±â€Š18.5 HU) and i-100-kVp (30.9 ±â€Š8.6 HU) protocols were higher than that of the120-kVp protocol (23.8 ±â€Š5.7 HU). There was no significant difference in SNR and the result of qualitative image analysis between the 120-kVp and i-100-kVp protocols.The 100-kVp protocol with HIR reduced the 76% radiation dose while preserving the image quality compared with the conventional 120-kVp protocol on retrospective ECG-gated cardiac CT.

Irradiation in presence of iodinated contrast agent results in radiosensitization of endothelial cells: consequences for computed tomography therapy.

PURPOSE: To date, iodinated contrast agents (ICA) are commonly used in medical imaging to improve tumor visualization by attenuating scanners X-rays. However, some adverse reactions to ICAs are still reported, and their molecular origin remains unclear. In 1983, it was proposed to visualize and treat ICA-loaded tumors by using scanners as therapy machines to enhance X-rays absorption at the iodine atoms. Theoretically, such physical conditions are optimized at 50 keV and can be easily obtained with synchrotrons. METHODS AND MATERIALS: Here, we examined the molecular and cellular responses of mammalian endothelial cells to radiation in the presence of iomeprol, one of the most extensively used ICAs. RESULTS: Irradiation with X-rays at 50 keV in the presence of iomeprol produced a strong radiosensitization effect. The same conclusion was reached with a standard medical irradiator but to a lesser extent. While such treatment did not produce additional DNA double-strand breaks, we observed a dose-dependent production of iodides due to the iomeprol radiolysis that inhibit double-strand break repair rate by decreasing DNA-PK kinase activity. CONCLUSIONS: Our data suggest that the concomitant use of ICA and radiation may be toxic when radiation-produced iodide concentrations and double-strand break yields are sufficient. The potential toxicity of ICAs during X-rays for diagnosis and therapy is discussed.

The effect of contrast media on the synovial membrane.

OBJECTIVE: To examine the effect of intra-articular injection of contrast media, sorbitol and normal saline on the synovial membrane. MATERIALS AND METHODS: Sixty three rabbits (126 knees) were used in this study. We injected the knees with amidotrizoate, ioxaglate, iopamidol, iotrol and diluted gadolinium-DTPA (2 mmol/l). Normal saline and sorbitol 27.25% were used for comparison. A histological and histochemical examination of the knees was carried out 1, 2, 10, 20, 30, 40 and 60 days after the injection. RESULTS: On histological examination, the knees injected with normal saline, ioxaglate and gadolinium-DTPA had a normal appearance. Intra-articular injection of amidotrizoate, iopamidol, iotrol and sorbitol caused early, mild and transient histological changes of the synovium (synovial hyperplasia, infiltration by leucocytes). Furthermore, the knees injected with amidotrizoate presented with late, extensive histological changes (severe synovial hyperplasia, moderate vascular dilatation, severe infiltration by leukocytes). CONCLUSION: The results suggest that the chemical structure and not the osmolality of the contrast media is the main cause for the histological changes of the synovium.

[Intrathyroidal iodine concentration after application of non-ionic contrast media with and without prophylactic application of perchlorate]. / Intrathyreoidale Iodkonzentration nach Applikation nichtionischer Kontrastmittel ohne und mit Perchlorat-Gabe.

AIM: This study was designed to show the effect of a nonionic contrast medium (Iomeprol-300; CM) on the intrathyroidal iodine concentration with and without a concomitant medication with perchlorate (1380 mg/d) to block the thyroidal iodine uptake. VOLUNTEERS AND METHODS: Twelve volunteers recieved 100 ml Iomeprol-300 intravenously and the perchlorate prophylaxis mentioned above. Another 12 volunteers got 100 ml Iomeprol-300 only. By means of X-ray-fluorescence-analysis the intrathyroidal iodine concentration was determined in advance as well as 0.2, 1, 3, 5, 7, 24, 48, 72, and 96 hours after the application of the CM. RESULTS, CONCLUSION: The intrathyroidal iodine concentration did not change in the group of volunteers on perchlorate medication. Without perchlorate the intrathyroidal iodine concentration decreased after the application of the CM when it was initially high (722 +/- 66 microg/ml before, 670 +/- 65 microg/ml after CM; p = 0.046) and increased in case of a low initial concentration (327 +/- 40 microg/ml before, 381 +/- 25 microg/ml after CM; p = 0.046). The effect is significant but its magnitude is too small to be harmful for a patient with a healthy thyroid. The oral application of 1.4 g/d perchlorate inhibits the thyroidal iodine uptake and the intrathyroidal iodine concentration is unaffected by the application of a CM.