Edge-enhanced spatiotemporal constrained reconstruction of undersampled dynamic contrast-enhanced radial MRI.

Dynamic contrast-enhanced magnetic resonance imaging (MRI) is a technique used to study and track contrast kinetics in an area of interest in the body over time. Reconstruction of images with high contrast and sharp edges from undersampled data is a challenge. While good results have been reported using a radial acquisition and a spatiotemporal constrained reconstruction (STCR) method, we propose improvements from using spatially adaptive weighting and an additional edge-based constraint. The new method uses intensity gradients from a sliding window reference image to improve the sharpness of edges in the reconstructed image. The method was tested on eight radial cardiac perfusion data sets with 24 rays and compared to the STCR method. The reconstructions showed that the new method, termed edge-enhanced spatiotemporal constrained reconstruction, was able to reconstruct images with sharper edges, and there were a 36%±13.7% increase in contrast-to-noise ratio and a 24%±11% increase in contrast near the edges when compared to STCR. The novelty of this paper is the combination of spatially adaptive weighting for spatial total variation (TV) constraint along with a gradient matching term to improve the sharpness of edges. The edge map from a reference image allows the reconstruction to trade-off between TV and edge enhancement, depending on the spatially varying weighting provided by the edge map.

Effects of iodinated contrast media on endothelium: An in vitro study.

The aim of this study was to determine the influence of radiographic contrast media (CM) on endothelial cells in order to compare the effects of non-ionic (Iomeron and Visipaque) and ionic (Hexabrix and Uromiro) CM on the endothelial cells (EC). Human and murine cells were exposed for 2, 4 and 24h to increasing concentrations (12.5, 25, 50 and 100mg/mL) of test compounds. Controls were incubated with complete growth medium or mannitol solution (osmotic control). MTT assay was used to evaluate the cell viability, LDH assay was used to evaluate the membrane damage. The results demonstrate a difference between non-ionic and ionic compounds in the effect on endothelium. Ionic CM show to strongly affect endothelial cells viability under all tested conditions, while non-ionic CM show effects only after prolonged exposure at 50 and 100mg/mL, which represent instant concentrations lasting just minutes after intravascular injection of CM. Taken together, these results confirm that the currently employed non-ionic contrast media are well tolerated by the vascular endothelium and have wide margins of safety.

Contrast-enhanced voiding US for grading of reflux in adult patients prior to antireflux ureteral implantation.

PURPOSE: To prospectively assess contrast material-enhanced voiding ultrasonography (US) for grading of vesicoureteral reflux (VUR) and to compare results with those of voiding cystourethrography (VCUG) in adult patients undergoing antireflux ureteral implantation. MATERIALS AND METHODS: Thirty-seven consecutive adult patients who had undergone renal transplantation with Politano-Leadbetter (18 patients) or Lich-Gregoire (19 patients) technique were included on the basis of previous urinary tract infections (UTIs) and time elapsed after renal transplantation. Exclusion criterion was current UTI. US was performed by one of two sonologists with injection of saline and microbubble suspension and was recorded on videotape. Sonologists assigned VUR diagnosis in consensus after videotape review. VCUG was performed by one of two radiologists immediately after US. Radiologists were blinded to US findings and assigned VCUG diagnoses in consensus. Contingency table was used to compare US and VCUG. Agreement between US and VCUG was determined with kappa statistics. RESULTS: With VCUG, VUR was diagnosed in 15 patients and not diagnosed in 22 patients. US and VCUG results were in agreement in 14 patients with VUR and 21 patients without VUR. US sensitivity and specificity for detection of VUR were 93% (14 true-positive results in 15 abnormal cases) and 95% (21 true-negative results in 22 normal cases), respectively. Agreement between US and VCUG was 95% (kappa = 0.89, P <.001). In 11 of 14 patients, VUR grades were in agreement for US and VCUG. In three of 14 patients, US indicated a higher grade than did VCUG. VUR was diagnosed in seven of 18 Politano-Leadbetter cases and eight of 19 Lich-Gregoire cases. CONCLUSION: A high rate of agreement was seen between voiding US and VCUG.

Meios de contraste de uso intravascular: breve histórico / Intravascular contrast media: a brief history

Desde os estudos iniciais de Osborne e cols., em 1923, com o uso do iodeto de sódio (NaI) como meio de contraste na avaliaçäo do sistema urinário, os meios de contraste radiológicos têm sido objeto de estudo contínuo, objetivando-se, principalmente, a melhoria da capacidade diagnóstica e a diminuiçäo dos efeitos adversos

Reacciones adversas a medios de contraste iónicos en urografía excretora: Hospital Roosevelt, abril 1996-febrero 1997 / Adverse reactions in excretory urography using ionic media contrast, April 1996-February 1997, Hospital Roosevelt

Objetivo: Determinar cual de los medios de contraste (MC) iónicos producía con mayor frecuencia y gravedad de reacciones adversas (RA) en la urografía excretora(UE),en el Hospital Roosevelt,Guatemala, desde abril de 1996 a febrero de 1997.Material y Métodos: Se realizó un estudio prospectivo seleccionando a 200 pacientes sometidos a UE, que fueron divididos en cuatro grupos(cada uno con n=50),según el MC yodado, hidrosoluble, iónico y alta osmolaridad administrado por vía intravenosa (IV) en dosis de 80 a 100 ml:1) iodamida,2) ioxitalamato,3), amidotrizoato y 4)diatrizoato. Se incluyeron pacientes mayores de 12 años, ambulatorios u hospitalizados, sin antecedentes de RA a los MC, asma, sensibilización al yodo y sin insuficiencia cardíaca congestiva. Se clasificacon las RA en leves, moderadas y graves, según la Organización Mundial de la Salud. Se estabaleció el puntaje de gravedad(PG):RA leve=2,RA moderada=4 y RA grave=8; el PG total(PGT) y el PG promedio (PGP). La gravedad se dividió en baja, intermedia y alta. Se usó distribución de frecuencias en porcentajes y chi cuadrado con p menor o igual de 0,05(5/100). Resultados: La frecuencia de RA fue de 31/100. Leves el 93/100, las moderadas el 7/100 y no hubo graves. El 38/100 de los pacientes con iodamida tuvo RA.La frecuencia de RA de los MC tuvo un valor de p=0,713.El amidotrizoato tuvo el PGP m s alto (4,4); el ioxitalamato tuvo el PGP mas bajo (3,3). El 54/100 de los pacientes tuvo gravedad baja y el 46/100 tuvo intermedia. Discusión: La frecuencia de RA a los MC iodamida, ioxitalamato, amidotrizoato y diatrizoato en la UE fue alta, mayor que lo reportado y sin diferencias importantes entre ellos.Las RA leves fueron muy frecuentes y las moderadas raras. La ausencia de RA graves indica la seguridad de los MC. No hubo diferencias importantes en la gravedad. El PG valoró con objetividad la gravedad de las RA a los MCiónicos usados en UE

[The effect of epsilon-aminocaproic acid and prednisolone on the activation of the complement system due to x-ray contrast agents in rats in vitro]. / Vliianie épsilon-aminokapronovoi kisloty i prednizolona na aktivatsiiu sistemy komplementa, vyzyvaemuiu rentgenokontrastnymi sredstvami u krys in vitro.

epsilon-Aminocaproic acid and prednisolone in concentration of 3.0 x 10(-5) M are proven to reduce or even completely prevent activation of the alternative pathway of the component which has been induced by iod-amide adipiodone and triombrast in concentrations 2.5 x 10(-2) M in the serum of "sensitive" rats. The preventive effect of the glucocorticoid appeared less pronounced. There exists direct positive correlation between the degree of the component activation with radiopaque compounds and preventive effect of the drugs studied.

[The mechanism of histamine liberation from rat mast cells under the action of x-ray contrast media]. / Mekhanizm vysvobozhdeniia gistamina iz tuchnykh kletok krys pod deistviem rentgenokontrastnykh sredstv.

It was demonstrated in rat experiments that a positive direct correlation exists between the decrease in the amount of histamine in rat peritoneal must cells after intravenous infusion of radiopaque agents (ROA) in a dose of 2 ml/kg and the amount of these penetrating from the blood into the peritoneal cavity. The degree of penetration is determined by the chemical structure and/or physiochemical properties of the ROA.

An automated multidimensional screening approach for rapid method development in high performance liquid chromatography.

Despite enormous advancements in the area of high performance liquid chromatography (HPLC) in recent years, method development remains a major challenge. This is primarily due to the unknown nature of the matrix material which sometimes is difficult to characterize (e.g. biological matrices). To improve the efficiency of method development a multidimensional screening approach was presented. This approach was based on two major steps: (1) a matrix spiked with drug was eluted from a large number of columns, each under different mobile phase compositions, to provide the preliminary selectivity-separation information; (2) this information was then used to compose column switching pairs (each pair consisted of a preparatory column followed by an analytical column) and the elution profile was evaluated to determine the suitable clean up and quantitation conditions. An example was provided using ethyl 3,5-bis(acetylamino)-2,4,6-triiodobenzoate (EEDA), an X-ray enhancement agent, in human plasma. Since the HPLC system was fully automated the data generation time, and consequently the method development time, can be significantly reduced.

[Restorative proctocolectomy. A morphological-functional study by computed tomography with coronal scans]. / Proctocolectomia ricostruttiva. Studio morfologico-funzionale con Tomografia Computerizzata con scansioni coronali.

Restorative proctocolectomy with ileal pouch has become the surgical treatment of choice for patients with ulcerative colitis and familial polyposis of the colon. Defecography is the radiologic technique commonly used to obtain detailed information on function and morphology of the ileal pouch, but it fails to depict the pelvis. Computed Tomography (CT), with coronal images only was used to examine 10 patients with ulcerative colitis, submitted to restorative proctocolectomy. Coronal CT, yielding a panoramic view of the pelvis, represent an effective alternative technique to defecography. In fact, the two techniques provide comparable information relative to the ileal pouch; coronal CT also depicts the possible thickening of pouch walls and of pelvic fat tissue. Coronal CT also depicts the continence of ileo-anal and ileo-ileal anastomoses and the functional changes of the perineal muscles at rest and during squeezing. Coronal CT images allow easy and clear detection of such major postoperative complications as pelvic inflammation and fistulae (less frequently stenosis or dehiscences of the anastomosis).

[The effect of cimetidine on the renal excretion of verografin and iodamide in dogs]. / Vliianie tsimetidina na pochechnuiu ékskretsiiu verografina i iodamida u sobak.

The intravenous injection of cimetidine in a dose of 20 mg/kg enhanced verografine and iodamide excretion in chronic canine experiments. The higher verografine and iodamide excretion was due to their increased renal tubular secretion. In dogs, cimetidine unchanged the secretion of cardiotrast, a test agent for anionic transport. Possible extrarenal mechanisms of action of cimetidine on verografine and iodamide transport were also examined.

[Use of iodamide 300 and iodamide 380 in galactography]. / Primenenie iodamida-300 i iodamida-380 dlia galaktografii.

The authors analyze the results of iodamide use for galactography. 434 females with discharge from the nipples were examined making use of galactography, and 136 women were selected for surgical treatment; the local processes in the mamma were previously unpalpated, nor were they confirmed by the laboratory findings. Clinical and morphologic analysis of the preparations resected in surgery has lead the authors to a conclusion that galactograms made with use of iodamide are sufficiently contrast and informative. The authors recommend this agent for the diagnosis of unpalpated mammary tumors.

[Adverse reactions to high osmolarity contrast media. A comparative-prospective study]. / Reacciones adversas a medios de contraste de alta osmalaridad. Estudio comparativo--prospectivo.

The purpose of this study was to verify and compare the different types of reactions to iodinated contrast media available at the Social Security Metropolitan Hospital Complex: Conray 60%, Vascoray and Uromiron. These are ionic, high osmolality compounds. The authors found that, in 400 patients not only the osmolality had an important role in the reactions observed, but that the intrinsic nature of the molecule of the contrast medium used was the determining factor.

Reacciones adversas a medios de contraste de alta osmalaridad. Estudio comparativo--prospectivo / Adverse reactions to high osmolarity contrast media. A comparative-prospective study

The purpose of this study was to verify and compare the different types of reactions to iodinated contrast media available at the Social Security Metropolitan Hospital Complex: Conray 60%, Vascoray and Uromiron. These are ionic, high osmolality compounds. The authors found that, in 400 patients not only the osmolality had an important role in the reactions observed, but that the intrinsic nature of the molecule of the contrast medium used was the determining factor

[The effect of x-ray contrast media on the amount of thromboxane and prostacyclin in the blood of man and rats in vivo and in vitro]. / Vliianie rentgenokontrastnykh sredstv na kolichestvo troboksana i prostatsiklina v krovi u cheloveka i krys in vivo i in vitro.

The in vivo and in vitro effects of radioopaque agents such as bilignost, iodamide, and triombrast on blood thromboxane B2 (TxB2) and prostacyclin levels were studied in man and rats. These radioopaque agents were demonstrated to increase prostacyclin levels and to decrease TxB2 in the plasma by 40%, as evidenced by urography when given in vivo (1-2 g/kg) and in vitro (2.5.10(-2) M and 2.5.10(-3) M).

[The possible mechanisms of the interaction of hepatotropic diagnostic agents with proteins]. / Vozmozhnye mekhanizmy vzaimodeistviia gepatotropnykh diagnosticheskikh sredstv s belkami.

The phenomenon of precipitation in protein solutions after addition of hepatotropic diagnostic media is described. The examination of different proteins and media allows the coagulative mechanism to be proposed, through which the electrostatic interactions between di- and polyvalent ligands with positively charged protein groups play the major role. It is suggested that the described phenomenon contributes to the nephrotoxicity of some drug groups.

Serious or fatal complications after inadvertent administration of ionic water-soluble contrast media in myelography.

The consequences of the inadvertent administration, by the intrathecal route, of ionic contrast media instead of iopamidol in seven subjects are reported. The ionic compounds were diatrizoate, iodamide and ioxitalamate. The outcome was fatal in three out of seven subjects, and it depended on the type and the dose of the administered contrast agent. The serious or fatal reactions observed are a tragic confirmation of the predictive power of neurotoxicity data obtained in animal studies with various iodinated water-soluble compounds. The margin of safety, represented by the ratio of LD50 i.ce. in mice to clinical dose in humans, both normalized to bodyweight, appears to reliably reflect the risk of toxic reactions after intrathecal administration of iodinated contrast agents.

Reacciones anafilactoides a los medios de contrastes iodados / Anaphylactoid reactions to ionic iodinated contrast

En este artículo se procede a realizar una discusión acerca de la frecuencia de las reacciones anafilactoides a los medios iodados para estudios radiológicos, su patogénesis, y las medidas para tratamiento que deben seguirse en el caso de que se presente esta urgencia durante un estudio radiológico. Se hace hincapié, sobre todo, el tratamiento preventivo para reducir al mínimo la probabilidad de tener este tipo de complicación que puede llevar a un rápido y mortal deterioro del paciente

[The urethrocystogram and perineal sonography compared]. / Urethrozystogramm und Perinealsonographie im Vergleich.

Perineal sonography and urethrocystography were performed on 45 patients in the same sitting to evaluate the sonographical method with regard to its applicability as a routine examination method. Corresponding results were obtained 14 times (= 30%). In 31 patients (= 70%) urethrocystographic and ultrasonic measurements diverged. The urethrocystogram must therefore remain an integral part in the work-up of urinary incontinence.