Gastrografin for uncomplicated adhesive small bowel obstruction in children.

PURPOSE: The risk of bowel injury during surgery for small bowel obstruction (SBO) has generated interest in conservative treatment modalities. Few data are available on conservative Gastrografin treatment for SBO in children. METHODS: We prospectively included patients with uncomplicated adhesive SBO managed at a pediatric center between March 2009 and September 2010. Patients who were unimproved after 48 h of conservative treatment received 50-100 ml of Gastrografin. If Gastrografin was seen in the cecum on the abdominal radiograph 4-6 h later, feeding was initiated and the patient was discharged on the same day. Each patient was matched to 2 controls on the number of previous SBO episodes. The primary outcome was length of hospital stay (>3 days), and the secondary outcome was time from admission to first feed (>2 days). Both were compared in the two groups using conditional logistic regression. RESULTS: The 8 patients admitted for SBO were matched to 16 controls. Gastrografin administration was associated with significantly lower risks of staying in the hospital longer than 3 days (P < 0.10) and waiting more than 2 days before the first feed. CONCLUSION: This preliminary study suggests that Gastrografin may be useful for managing adhesive SBO in children.

Influence of dosage and chemical restraints on feline excretory urography.

Three series of trials involving 10 domestic short-haired cats were carried out to determine the influence of dosage of contrast media or type of chemical restraint on feline excretory urography. The 1st series (group A) involved 5 cats sedated with 2.0 mg/kg intramuscular (i.m) injection of 2% xylazine and receiving 800 mg/kg of 76 % meglumine diatrizoate (urografin). The 2nd series (group B) involved another 5 cats sedated with 2.0 mg/kg (i.m) injection of 2% xylazine and receiving 1200 mg/kg of 76% urografin. The 3rd series (group C) involved the repeat urography of the group B cats but sedated with 15 mg/kg (i.m) injection of 5% ketamine hydrochloride. Ventrodorsal radiographs were obtained immediately, 5, 15 and 40 minutes after the injection of 76% urografin. Scores were assigned to nephrographic opacification as described in the literature. The heart rates, respiratory rates and rectal temperatures of the cats were also determined before sedation, after sedation, immediately after the injection of 76% urografin and at 15-minute intervals over a period of 60 minutes. In this study, there were significant differences (P < 0.05) in the nephrographic opacification scores between the group A and group B cats at times 0 and 40 minutes post-administration of urografin. Group A cats had good initial nephrographic opacification which faded later while the nephrographic opacification of group B cats progressively increased. Similarly, nephrographic opacification was significantly (P < 0.05) higher in the xylazine-sedated cats (groups A and B) than the ketamine-sedated cats (group C). However, there were no significant differences (P > 0.05) in heart rates, respiratory rates and rectal temperatures between the 3 groups of cats. It was therefore concluded that increasing the dosage of urografin above 800 mg/kg in cats does not provide additional beneficial effects on the nephrograms produced. Xylazine sedation was observed to produce better nephrographic opacification, however, with delayed nephrographic fading compared to ketamine sedation.

[Triombrast in diagnosis of urological diseases].

Radiocontrast substances have a significant role in x-ray diagnosis of urological diseases. Diagnostic and cost-effect efficacy, delivery, storage life are described for radiocontrast substance triombrast (sodium amidotrizoate) of Ukraine production (Kiev). The review was based on the authors' experience and results of clinical trials.

Quality of urography and renal clearance of ionic and nonionic contrast media.

The authors evaluated whether urographic quality correlated with patient hydration and the level of their renal function, depending on whether they received ionic or nonionic contrast media. One hundred patients with normal serum creatinine levels were randomly assigned to receive intravenous urography with either an ionic high-osmolar or a nonionic low-osmolar contrast medium. Patient hydration was evaluated by measuring urine osmolality in a sample voided just before the examination. The plasma concentration of iodine was determined in a single blood sample drawn approximately 3 hours later. From these determinations the plasma clearance of contrast medium was calculated. The urograms were assessed blindly with regard to nephrographic and pyelographic opacification, as well as overall diagnostic quality. The clearance varied between 42 and 115 mL x minutes-1 x 1.73 m-2. No systematic correlation of practical significance was found between the clearances and the urogram quality. A high urinary osmolality before the examination tended to improve quality with both media. It is not possible to assess glomerular filtration rate from nephrographic and pyelographic opacification, or from overall quality of routine urograms in patients with normal serum creatinine levels.

Does dilution of contrast media affect contrast enhancement? An experimental study in rats.

The effect of contrast media (CM) dilution on contrast enhancement was studied using CM representing four structurally different molecular types at osmolalities ranging from 135 to 1340 mosm/kg. Diatrizoate (ionic monomer), iopamidol (nonionic monomer), ioxaglate (ionic dimer), and iodecol (nonionic dimer) were each given at a dose of 500 mgI/kg and at concentrations of both 300 and 150 mgI/mL. Contrast media concentrations were measured using iodine 125I. Tissue blood volumes were determined using human serum albumin labeled with 131I. For each of the four CM at each of the two concentrations and after each of five time intervals following injection (0, 15, 40, 120, and 300 seconds), five rats were killed (total = 200 rats). Blood and 14 other tissues were studied. Dilution of the CM did not lead to any lower iodine tissue concentrations, iodine distribution volumes, plasma volumes, or hematocrit. The authors conclude that lowering CM osmolality by dilution with water should improve tolerance without affecting CT contrast enhancement.

Renal clearance of an ionic high-osmolar and a nonionic low-osmolar contrast medium.

One hundred patients with normal serum creatinine concentration underwent intravenous urography with either an ionic high-osmolar (diatrizoate) or a nonionic low-osmolar (iopamidol) contrast medium after randomization. Before injection of the contrast medium, a blood sample was drawn for determinating serum creatinine concentration, and a urine sample for measurement of urine osmolality. Using x-ray fluorescence, the plasma concentration of iodine (contrast medium) was determined on blood samples drawn approximately 3 and 4 hours after injection of the contrast medium. The glomerular filtration rate was calculated by two different formulas: one requiring only a single sample and one requiring at least two samples (standard). There were poor correlations between the standard contrast medium clearance and the serum creatinine concentration, the estimated creatinine clearance (calculated from a nomogram), as well as the urine osmolality. The 3-hour and the 4-hour single-sample values correlated well with the two-sample values for both contrast media. In patients with normal serum creatinine, the glomerular filtration rate determined by measuring the contrast medium concentration in a single plasma sample obtained at 3 hours, is almost identical to the value determined from two samples. Consequently, two samples are unnecessary.

Application of pharmacokinetics to computed tomography: injection rates and schemes: mono-, bi-, or multiphasic?

OBJECTIVE: The objective of the current study was to test whether optimization of dose regimens for detecting focal liver lesions by computed tomography is possible by using the available time-density data of former studies published in the literature and a computer program so that the number of further clinical tests with the exclusive objective of optimizing injection schemes could be reduced. METHODS: Computed tomography enhancement data of the aorta and/or the liver obtained after injecting a conventional ionic and a nonionic contrast agent were used to calculate pharmacokinetic parameters and to simulate the time course of enhancement for a variety of different infusion regimens modifying contrast medium strength, dose, and injection rate. The study consisted of two parts. In the first part, mean relative enhancement curves of the aorta and of liver parenchyma (0 to 300 sec) using meglumine diatrizoate (306 mg iodine per mL, 300 mg iodine per kg) were taken from the literature and their values were approximated using the computer program TOPFIT. In the second part, equivalent data for iohexol including a total of three strengths (240, 300, and 350 mg iodine per kg) and doses from 30 to 45 grams of iodine were used. "Validation" of the simulation method was obtained, first by comparing measured and calculated maximum intensities and times to reach maximum and, second, by using one injection scheme for the simulation of a second and comparing the results with actually measured data. RESULTS: The computer program TOPFIT allowed for excellent curve fitting of the measured density values. The data obtained in the first part of the study showed that after a dose of 300 mg I/kg and a rate of 2 mL/sec maximal enhancement is achieved in the aorta after 30 seconds (approximately 100 HU) and in the liver after 50 seconds (approximately 30 HU). The higher the dose and the rate of infusion were, the higher was the enhancement. The difference in density between aorta and liver was proportional to the infusion rate approaching asymptotically approximately 90 HU at 8 mL/sec for a dose of 300 mg I/kg. Bi- or triphasic infusion schemes did not improve differences in enhancement. The curve fitting obtained in the second part of the study also confirmed the results reported in the literature. A "crossover" prediction of data was possible within the range of interindividual variations of pharmacokinetic parameters and thus validated the chosen approach of computer simulation. Furthermore, data sets selected randomly out of the simulation results could be used--within the limits of interindividual variability--to predict data determined in other clinical trials. CONCLUSION: The computer program TOPFIT appears useful for the optimization of time--density profiles in computed tomography. The number of further clinical studies with the objective of optimization could therefore possibly be reduced.

Effects of diatrizoate and iopamidol on spermatogenesis.

RATIONALE AND OBJECTIVES: The biological effects of iodinated contrast media were examined by using spermatogenesis in mouse testis as the experimental model. METHODS: Spermhead survival and abnormality assays were used as the biological end points. Diatrizoate meglumine/diatrizoate sodium and iopamidol were administered intravenously at equal rates and concentrations. Testicular uptake and clearance of these contrast agents were examined by high-performance liquid chromatography techniques. Appropriate mannitol solutions were employed as osmolality controls. RESULTS: Intravenous administration of the contrast agent or its respective mannitol control resulted in approximately a 30% decrease in spermhead count. A dose-related experiment with mannitol demonstrated that the spermhead count decreased rapidly until 600 mOsm/kg was reached, beyond which this decrease was minimal. Clearance of both contrast media was complete in approximately 4 hours. No significant increase in the induction of spermhead abnormalities was observed. CONCLUSION: Osmotic substances, such as iodinated contrast agents, affect the process of spermatogenesis.

Intrathecal injection of high-dose meglumine amidotrizoate with complete recovery.

Rarely we are faced with accidental spinal injection of potentially toxic substances. We present 2 cases in which amidetrizoate, water-soluble ionic contrast medium, was accidentally injected intrathecally. Our treatment consisted of vigorous hydration and barbiturate coma. This report suggests that for water-soluble ionic contrast media increasing cerebrospinal fluid circulation by vigorous hydration may be as effective as spinal lavage in diminishing toxicity.

Comparative effects of glycerol and Urografin on cochlear blood flow and serum osmolarity.

Glycerol, an osmotic diuretic, has been used for the diagnosis and treatment of endolymphatic hydrops. Hearing improvements in hydropic ears are attributed to its dehydrating effect. In addition to this effect, glycerol also increases cochlear blood flow. Urografin, another hyperosmotic agent used for vasography, is similarly known to increase local blood flow. The present study compared these two hyperosmotic agents, glycerol and Urografin, in their effects on cochlear blood flow and serum osmolarity. Laser Doppler flowmetry on the lateral wall of the cochlea revealed that the increase in cochlear blood flow with a 30-min infusion (0.025 ml/min) of 76% Urografin continued for a longer time than with a 30-min infusion (0.025 ml/min) of 50% (v/v) glycerol. The significant increases appeared at 20 and 30 min after the infusion with the former; 10, 20, 30, 40, 50 and 60 min after the infusion with the latter. Intravenous infusion of these agents also caused elevation in serum osmolarity. This elevation was appreciably greater with Urografin infusion (maximal increase: about 30 mOsm on average) than with glycerol infusion (maximal increase: about 6 mOsm on average), and the former elevation appeared to be longer lasting than the latter. These differences were ascribed to differences between glycerol and Urografin with respect to the creation of an osmotic gradient across the capillary walls of cochlear blood vessels. Since glycerol penetrates the interstitial space and moves into inner ear fluids, the gradient may decline faster. It would be assumed that a higher concentration of the hyperosmotic agent in the capillary blood causes more vasodilatation and lowering of blood viscosity. Alternatively, direct action of these agents on the vascular wall may affect some biological processes, leading to vasodilatation in different degrees and durations with different agents. Hearing improvement with glycerol administration in hydropic ears was also discussed from the perspective of cochlear blood flow.

Spiral computed tomography of the liver: contrast agent pharmacokinetics and the potential for improved hepatic enhancement.

RATIONALE AND OBJECTIVES: We conducted a prospective study of 131 patients to evaluate the contrast agent dose-response relationship for liver spiral computed tomography (CT) and to test the hypothesis that spiral CT scanning provides greater enhancement than does dynamic CT scanning. METHODS: Patients were assigned to one of two control groups (dynamic CT) or to one of five experimental groups (spiral CT). Dynamic CT patients received 150 ml and spiral CT patients received either 75, 100, or 150 ml of diatrizoate meglumine. All groups had a monophasic injection rate of 2.5 ml/sec. Hepatic enhancement was compared among experimental and control groups. RESULTS: In the experimental groups, there was a linear dose-response relationship (p < .0001) among the enhancements achieved for the three dosages. The enhancement of the last slice of liver for the spiral CT versus dynamic CT groups receiving 150 ml was significantly greater (p = .002). Peak, first liver slice, and average liver enhancement values were higher with spiral CT scanning, but the difference was not statistically significant (power > .55). CONCLUSION: Using uniphasic injection rates and identical doses of contrast agent, spiral CT scanning has the advantage of improved enhancement of the last part of the liver to be imaged.

[Urography and renal clearance of contrast media. A randomized comparison of an ionic high-osmolar and a non-ionic low-osmolar contrast medium]. / Urografi og renal clearance af røntgenkontraststof. En randomiseret undersøgelse mellem et ionisk højosmolaert og et ikke-ionisk lavosmolaert røntgenkontraststof.

One hundred patients with confirmed or presumedly normal serum creatinine level had an intravenous urography with either an ionic high-osmolar or an non-ionic low-osmolar contrast medium after randomization. Employing Renalyzer PRX 90, the plasma concentration of iodine were determined on blood samples drawn approximately three and four hours after the injection of the contrast medium. From these, the glomerular filtration rate was calculated. The urograms were assessed blindly as regards nephrographic and pyelographic opacification as well as the overall quality as regards the diagnosis was assessed. The clearance was found to vary between 42 and 125 ml x min-1 x 1.73 m-2. No systematic connection of practical significance was found between the clearance and assessment of the urograms. Considerable variation was found in the clearance among not only the poor but also the good urograms. No demonstrable differences of clinical significance were found between the two contrast media. It is concluded that it is not possible to assess clearance from the appearance of the nephrogram and pyelogram or from the overall diagnostic quality in routine urographies regardless of whether ionic high-osmolar or non-ionic low-osmolar contrast media are employed in patients with normal serum creatinine levels.

Renal excretion of water-soluble contrast media after enema in the neonatal period.

BACKGROUND: When abdominal distention occurs or bowel obstruction is suspected in the neonatal period, a water-soluble contrast enema is helpful for diagnostic and therapeutic purposes. The water-soluble contrast medium is evacuated through the anus as well as excreted via the kidneys in some babies. This study was designed to evaluate the incidence of renal excretion after enemas using water-soluble contrast media and presume the causes. METHODS: Contrast enemas using diluted water-soluble contrast media were performed in 23 patients under 2 months of age. After the enema, patients were followed with simple abdominal radiographs to assess the improvement in bowel distention, and we could also detect the presence of renal excretion of contrast media on the radiographs. Reviewing the medical records and imaging studies, including enemas and consecutive abdominal radiographs, we evaluated the incidence of renal excretion of water-soluble contrast media and counted the stay duration of contrast media in urinary tract, bladder, and colon. RESULTS: Among 23 patients, 12 patients (52%) experienced the renal excretion of water-soluble contrast media. In these patients, stay-in-bladder durations of contrast media were 1-3 days and stay-in-colon durations of contrast media were 1-10 days, while stay-in-colon durations of contrast media were 1-3 days in the patients not showing renal excretion of contrast media. The Mann-Whitney test for stay-in-colon durations demonstrated the later evacuation of contrast media in the patients with renal excretion of contrast media (p = 0.07). The review of the medical records showed that 19 patients were finally diagnosed as intestinal diseases, including Hirschsprung's disease, meconium ileum, meconium plug syndrome, and small bowel atresia or stenosis. Fisher's exact test between the presence of urinary excretion and intestinal diseases indicated a statistically significant difference (p = 0.04). CONCLUSION: The intestinal diseases causing bowel obstruction may increase the water-soluble contrast media's dwell time in the bowel and also increase urinary excretion.

Low-frequency pulsed ultrasound in the nasal cavity and paranasal sinuses: a feasibility and distribution study.

BACKGROUND: Bacterial biofilms have been implicated in refractory rhinosinusitis. Biofilms have been shown to respond to treatment with low-frequency ultrasound (LFU) therapy in vitro, and exposure to LFU has shown efficacy in wound repair and topical drug delivery in other fields. This preliminary study was designed to evaluate the safety and feasibility of LFU for use in the nasal cavity and paranasal sinuses. METHODS: This was an experimental observational study. Six cadaver heads were used to deliver a mixture of Renografin and methylene blue solvent to the paranasal sinuses via LFU both before and after resident endoscopic sinus dissection. Sinus computed tomography (CT) scans of the cadaver heads were performed before and after mixture delivery, and blinded assessments were made for distribution to individual sinuses. Mucosa was harvested from 2 subsites to evaluate LFU-treated cadaver tissue. RESULTS: Predissection, LFU delivered solution to 12 of 12 inferior and middle turbinates, 6 of 12 of the superior turbinates and ethmoid sinuses, and 1 of 12 maxillary sinuses as shown by contrast radiography. Postdissection, all heads showed delivery to the maxillary and sphenoid sinuses, with 8 of 12 sinus cavities showing delivery to the ethmoid region, and 4 of 11 to the frontal recess. Using hematoxylin and eosin (H&E) staining of tissue frozen sections, harvested tissue demonstrated no architectural damage to the mucosal layer from LFU exposure. CONCLUSION: LFU appears to be capable of reliably delivering topical solution to the turbinates and ethmoid region preoperatively and to all sinuses, except the frontal, postoperatively. The nasal epithelium does not appear to be disrupted histologically from LFU at this time and distance. This data provides a foundation for a prospective human protocol studying the efficacy of this modality in the treatment of patients with chronic rhinosinusitis and biofilm formation.

Oral contrast adherence to polyps on CT colonography.

Although oral contrast agents are known to improve the accuracy of CT colonography (CTC) by tagging fluid and stool, it is not well recognized that oral contrast also adheres to the surface of polyps. The authors' objective was to quantitate the frequency of contrast adhering to polyps. Three hundred thirty-eight optical colonoscopy-proven polyps were identified on CTC of all of the 216 patients with polyps in a larger cohort of screening patients. CT scans of polyps were analyzed for adherent contrast (ie, a thin coat/adherent drops) in at least one view (prone/supine). Forty-six percent of the 312 polyps not touching a contrast pool had adherent contrast. Polyps with villous histology were significantly more likely to have adherent contrast (77% [20/26] vs. 43% [124/286], P<0.001). Oral contrast agents often tag polyp surfaces in a pattern that is distinct from internal tagging of adherent stool, which must be recognized during CTC interpretation. Polyps with villous histology show a higher rate of contrast adherence than nonvillous polyps.

Contrast media as markers for glomerular filtration: a pharmacokinetic comparison of four agents.

In this study methods for the assay of the iodine-containing radiographic contrast agents metrizoate, amidotrizoate and iothalamate found in serum and urine have been developed. The method involved reverse-phase high-pressure liquid chromatography with spectrophotometric detection. This technique was used to compare the clearance of these agents, in a group of healthy female volunteers, after a single small-dose injection (5 ml, 2275-3235 mg). In the period 0-4 h after injection, serum elimination was approximated by a two-compartment model. However, a full description of drug fate in the body required at least three compartments. Plasma clearance was significantly different between agents with means of 191, 130, 144 and 121 ml/min for metrizoate, amidotrizoate, iothalamate and iohexol, respectively, whereas no difference was found between the renal/plasma clearance ratio. Protein binding measured with equilibrium dialysis did not suggest binding to serum proteins by any of these agents irrespective of concentration.

Diffusion properties of transurethral intraprostatic injection.

OBJECTIVES: To evaluate the location and extent of diffusion that occurs when liquid is injected transurethrally into the prostate gland, by correlating real-time fluoroscopy and gross pathology, and to quantify the variables that influence intraprostatic diffusion during chemoablation of the prostate. MATERIALS AND METHODS: A solution of diatrizoate meglumine (Hypaque, Nycomed, Princeton, NJ) gentamicin and methylene-blue dye (HGM) was injected transurethrally into the prostate in six dogs, using a passive-deflection needle injection system. The intraprostatic diffusion characteristics were evaluated during each injection using real-time C-arm fluoroscopy, and following each injection by gross examination of methylene blue staining within the prostatic tissues. HGM back-flow into the urethra at the time of injection was assessed by measuring gentamicin levels in the collected bladder irrigant after each injection, using a standard dilution formula. RESULTS: There was variability in the intraprostatic diffusion both fluoroscopically and grossly. The needle occasionally assumed a straighter trajectory than its intended curve. Intraprostatic diffusion was detected in 12 of 36 injections (33%). Using standard manipulations of various devices increased the intraprostatic diffusion in these injections to almost 80%. There was less intraprostatic diffusion when the injection resistance was either extremely high or absent. There was no extraprostatic extravasation of HGM beyond the prostatic capsule. CONCLUSION: Current methods of transurethral intraprostatic injection are variable for both the diffusion of HGM solution and in needle deployment. The gross diffusion patterns with the HGM solution were consistent with the diffusion patterns documented in our previous research using absolute ethanol. These and other factors may partly explain the variability of the lesions produced with ethanol injection. Therefore, more research is needed to further elucidate the diffusion characteristics of solutions injected intraprostatically using the transurethral approach.