A direct injection liquid chromatography tandem mass spectrometry method for the kinetic study on iodinated contrast media (ICMs) removal in natural water

Iodinated contrast media (ICMs) are a class of X-ray contrast media worldwide utilized for radiographic procedures. Since they cannot be removed efficiently during water treatment, they can be found in surface and groundwater. In this work, a rapid and sensitive direct injection liquid chromatography-tandem (LC-MS/MS) method for the simultaneous analysis of seven ICMs media (iopamidol, ioxitalamic acid, diatrizoic acid, iothalamic acid, iohexol, iomeprol and iopromide) in complex aqueous matrices has been developed and validated. The MDLs for the analytes ranged from 0.7 to 21 ng L^-1 in ultrapure water, and recoveries ranged from 86 to 100% in drinking water, 85-103% in groundwater and 84-105% in WWTP effluent. A stereo-isomer for iopromide was separated. This analytic method was applied to investigate the removal of target ICMs by low pressure ultra violet light (LPUV) advanced oxidation processes with three oxidants, hydrogen peroxide, free chlorine and monochloramine in groundwater. Results showed that the addition of oxidants did not enhance attenuation of ICMs, since fluence-based decay apparent rate constants were similar (K_UV = 3.2 × 10^-3, K_UV-Cl2 = 3.6 × 10^-3 and K_UV-NH2 = 3.4 × 10^-3 10^-3 cm² mJ^-1). This yielded direct photolysis is the main mechanism to attenuate target ICMs.

Arterial enhancement at abdominal CT angiography: Low- versus high-osmolality contrast media

Purpose: To evaluate the effects of contrast media pharmokinetic differences on aortic enhancement at abdominal CT angiography and to determine whether these effects are of clinical relevance.

Material and Methods: Two hundred and twelve patients referred for abdominal CT angiography were included in the study. All abdominal CT angiograms were performed with the same parameters (collimation 3 mm, pitch ratio 1.7, scan delay 30 s) after i.v. injection of 120 ml of contrast medium at 3 ml/s. After randomization, patients received either iobitridol 300 (low-osmolar, 300 mg I/ml), iobitridol 350 (low-osmolar, 350 mg I/ml) or ioxithalamate 350 (high-osmolar, 350 mg I/ml). The time attenuation curves obtained with the three contrast media were compared.

Results: The time attenuation curve obtained with ioxithalamate 350 was not parallel to those obtained with iobitridol 300 and iobitridol 350. Mean peak enhancements obtained with iobitridol 350 and ioxithalamate 350 were not significantly different but iobitridol 350 provided higher mean peak enhancement than iobitridol 300. Mean delays of the peak enhancements were the same with the three contrast media. After peak enhancement, the decrease of aortic opacification under a selected threshold of 200 HU was significantly slower with iobitridol 350 than with iobitridol 300 and ioxithalamate 350, whereas iobitridol 300 and ioxithalamate 350 showed no significant differences.

Conclusion: For a given iodine concentration, low-osmolality contrast media provide longer aortic opacification and may be recommended for CT angiography when long acquisition times are needed.

Do intravenous N-acetylcysteine and sodium bicarbonate prevent high osmolal contrast-induced acute kidney injury? A randomized controlled trial

BACKGROUND

N-acetylcysteine (NAC) or sodium bicarbonate (NaHCO3), singly or combined, inconsistently prevent patients exposed to radiographic contrast media from developing contrast-induced acute kidney injury (CI-AKI).

OBJECTIVE

We asked whether intravenous isotonic saline and either NaHCO3 in 5% dextrose or else a high dose of NAC in 5% dextrose prevent CI-AKI in outpatients exposed to high-osmolal iodinated contrast medium more than does saline alone.

METHODS

This completed prospective, parallel, superiority, open-label, controlled, computer-randomized, single-center, Brazilian trial (NCT01612013) hydrated 500 adult outpatients (214 at high risk of developing CI-AKI) exposed to ioxitalamate during elective coronary angiography and ventriculography. From 1 hour before through 6 hours after exposure, 126 patients (group 1) received a high dose of NAC and saline, 125 (group 2) received NaHCO3 and saline, 124 (group 3) received both treatments, and 125 (group 4) received only saline.

RESULTS

Groups were similar with respect to age, gender, weight, pre-existing renal dysfunction, hypertension, medication, and baseline serum creatinine and serum cystatin C, but diabetes mellitus was significantly less prevalent in group 1. CI-AKI incidence 72 hours after exposure to contrast medium was 51.4% (257/500), measured as serum creatinine > (baseline+0.3 mg/dL) and/or serum cystatin C > (1.1 · baseline), and 7.6% (38/500), measured as both serum creatinine and serum cystatin C > (baseline+0.3 mg/dL) or > (1.25 · baseline). CI-AKI incidence measured less sensitively was similar among groups. Measured more sensitively, incidence in group 1 was significantly (p<0.05) lower than in groups 2 and 3 but not group 4; adjustment for confounding by infused volume equalized incidence in groups 1 and 3.

CONCLUSION

We found no evidence that intravenous isotonic saline and either NaHCO3 or else a high dose of NAC prevent CI-AKI in outpatients exposed to high osmolal iodinated contrast medium more than does saline alone.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01612013.

[Perioperative cholangiography: a case study at Yaounde (Cameroon)]

For many years peroperative cholangiography has been routinely used for bile duct surgery in the Western countries. However recent publications showing high rate of inconclusive peroperative cholangiography (47%) has cast doubt on this attitude. Surgeons in Africa and particularly in Cameroon have already replaced peroperative cholangiography with other indicators such as clinical history and preoperative echography, anticipating cholangitis. For some indications, e.g. Mirizzi syndrome, peroperative cholangiography is essential for surgery. The fluoroscopes required for this exploration should be made available in our hospitals since they are also needed for traumatology, vascular surgery, and other specialities. In addition this syndrome may be more common in our region.

Differential effects of N-acetylcysteine, theophylline or bicarbonate on contrast-induced rat renal vasoconstriction

BACKGROUND

Vasoconstriction and reactive oxygen species (ROS) accumulation following contrast media (CM) injection are the key factors triggering CM-induced nephropathy. We compared the effects of N-acetylcysteine (NAC), theophylline or sodium bicarbonate on intrarenal vasoconstriction and ROS generation in a rat model of CM-induced nephropathy.

METHODS

Following a 3-day dehydration, Sprague-Dawley rats received CM (Telebrix) or sham 'CM' injection of 0.9% saline. Part of them received NAC, theophylline or bicarbonate prior to CM. Medullar renal blood flow was estimated by laser Doppler. The animals were sacrificed 1, 15 or 30 min after the respective treatments, their kidneys allocated and intrarenal STAT-8 isoprostane, PGE(2) and NO assessed.

RESULTS

Vasoconstriction was significantly attenuated by NAC. Theophylline only mildly attenuated the perfusion drop at 15 min, and was ineffective following 30 min. Unlike theophylline or bicarbonate, NAC significantly augmented intrarenal PGE(2). NAC, theophylline but not bicarbonate, gradually increased intrarenal NO. In all experimental variables, CM-induced ROS accumulation, represented by STAT-8 isoprostane estimation, progressed undisturbed.

CONCLUSIONS

(1) CM-induced intrarenal vasoconstriction was efficiently prohibited by NAC but not bicarbonate or theophylline; (2) the vasodilatory effect of NAC was mediated via increased PGE(2) synthesis, and (3) ROS accumulation was a primary renal response to CM-induced injury, not affected by any pharmacologic manipulations.

Inadvertent intrathecal administration of ionic contrast medium to a dog

A hyperosmolar ionic contrast medium, ioxithalamate (Telebrix), was inadvertently injected intrathecally to a dog during myelography. The resultant severe adverse effects were myoclonus, uncontrollable seizures, and hyperthermia. These symptoms have been described by some authors as "ascending tonic-clonic seizure syndrome". The dog completely recovered within 24 h. The literature on 47 humans receiving intrathecal ionic contrast medium after 1966, one dog and one horse was reviewed, including the drugs involved, the circumstances of their use, and the symptoms, treatment and outcome of patients who received the drugs intrathecally. Recommendations to prevent such a misuse are given. The present report and review are a reminder that ionic contrast media are absolutely contraindicated for myelography. Only nonionic contrast media can be used intrathecally. All of the hyperosmolar contrast media are ionic and therefore contraindicated for myelography.

Iodide mumps after contrast media imaging: a rare adverse effect to iodine

BACKGROUND

Exposure to iodinated contrast media may elicit a variety of adverse reactions. Anaphylactoid and delayed cell-mediated unwanted effects are common; rare adverse reactions include iodine-related sialadenopathy, iododerma, and acneiform eruptions.

OBJECTIVES

To describe the occurrence of iodide mumps in a patient examined using contrast-enhanced computed tomography and to outline differential diagnoses.

METHODS

A detailed diagnostic approach, including histologic analysis, skin tests, controlled reexposure, efficacy of premedication, and imaging studies, is presented. The findings unique to this reaction and differential diagnoses are highlighted.

RESULTS

While undergoing repeated contrast-enhanced computed tomography a patient developed recurrent swellings of the sublingual glands, identified as iodide mumps. These swellings resolved within a few days. Imaging studies and histologic analysis showed distinct patterns without inflammation. The important role of iodine in this adverse reaction is demonstrated.

CONCLUSIONS

Iodine from iodinated contrast media may rarely elicit noninflammatory edema of the salivary glands. The reaction should be differentiated from other swellings in the head and neck area.

[Renal radionuclide scintigraphy in the evaluation of radiopaque substances on renal function]

To evaluate the nephrotoxic effect of radiopaque substances (ROS) by renal radionuclide scintigraphy, 47 patients were examined before and after coronary ventriculography. Iohexol, iobitridole, and ioxythalamate were used as ROS in 15, 18, and 14 patients, respectively. The parameters of renal filtration and excretory function were calculated during study. Ioxythalamate was shown to have a less pronounced nephrotoxic effect.

Analysis of iodinated X-ray contrast agents in water samples by ion chromatography and inductively-coupled plasma mass spectrometry

In this paper, an analytical method for the determination of six iodinated X-ray contrast agents (amidotrizoic acid, iohexol, iomeprol, iopamidol, iopromide, and ioxitalamic acid), iodide, and iodate in water samples is presented. The method is based on a separation of the analytes by ion chromatography (IC) and a subsequent detection by inductively-coupled plasma mass spectrometry (ICP-MS). The method was optimised with respect to separation conditions (column type and eluent composition) and extensively validated. Without pre-concentration of the samples, limits of detection below 0.2 microg/l could be achieved whereby reproducibility was below 6% for all compounds under investigation.

Telebrix Gastro in the management of adhesive small bowel obstruction

BACKGROUND

This study aimed to determine whether an abdominal radiograph 8 hours after ingesting oral Telebrix Gastro is a reliable marker for non-operative management in patients with adhesive small bowel obstruction.

METHODS

During a 5-year period (January 1, 1995, through December 31, 2000), 97 patients were admitted for small bowel occlusion due to adhesion with no indication for immediate surgery. All received 100 mL of Telebrix Gastro via gastric tube for small bowel obstruction due to adhesion. If the contrast reached the colon within 8 hours on plain abdominal radiograph, the test was considered to be negative.

RESULTS

126 cases of small bowel occlusions were analyzed due to recurring episodes for 11 patients. The test was negative in 113 cases (89.7%), and in this group, only two patients underwent surgery, the remaining being managed non-operatively. The 13 cases (10.3%) with a positive test for occlusion underwent surgery. The sensitivity, specificity and accuracy of the finding of contrast media reaching the colon as an indicator for conservative treatment were 98%, 100%, and 98%, respectively.

CONCLUSIONS

A water-soluble contrast study can be of significant help in the clinical management of patients suspected of having small bowel obstruction.

The value of contrast-enhanced helical CT scan with rectal contrast enema in the diagnosis of acute appendicitis

BACKGROUND

The aim of this retrospective study is to assess the accuracy of single slice helical CT scan with intravenous, and rectal contrast (CTRC) in the diagnosis of acute appendicitis (AA) in patients with suspected AA, with particular analysis of the diagnostic signs.

PARTICIPANTS AND METHODS

Abdomino-pelvic helical CTRC was performed on 75 consecutive patients with suspicion of AA. Radiologic diagnosis was compared with surgical/pathologic results and clinical follow-up. In addition, the CTRC examinations were retrospectively reviewed independently by two experienced radiologists using predefined diagnostic criteria. The sensitivity, specificity, and frequency of each diagnostic sign were calculated. The interobserver agreement and the statistical significance of the frequency for each diagnostic criterion were assessed using the Kappa and Fisher tests, respectively.

RESULTS

The accuracy of helical CTRC in the diagnosis of AA was 94.7%, sensitivity 100%, specificity 90%, PPV 89.7%, and the NPV 100%. Wall enhancement and nonopacification of the appendix recorded the highest sensitivity and specificity (97% and 100%, 94% and 95%, respectively). Appendiceal thickness greater than 6 mm was present in 100% of true-positive cases. However, 26.5% of true-negative cases had also an appendiceal diameter exceeding 6 mm, a value used as a cut-off for normal appendiceal diameter. The highest interobserver agreement was recorded for appendiceal wall enhancement and for nonopacification of the appendix (K=0.97 and 0.88, respectively).

CONCLUSIONS

CTRC is an accurate and relatively fast technique for investigation of patients with suspected AA. A negative CTRC can exclude completely the diagnosis of AA. Nonopacification of the appendix and appendiceal wall enhancement are highly sensitive, specific, and reproducible, signs representing major criteria for the diagnosis of AA.

PET/CT with intravenous contrast can be used for PET attenuation correction in cancer patients

PURPOSE

If the CT scan of a combined PET/CT study is performed as a full diagnostic quality CT scan including intravenous (IV) contrast agent, the quality of the joint PET/CT procedure is improved and a separate diagnostic CT scan can be avoided. CT with IV contrast can be used for PET attenuation correction, but this may result in a bias in the attenuation factors. The clinical significance of this bias has not been established. Our aim was to perform a prospective clinical study where each patient had CT performed with and without IV contrast agent to establish whether PET/CT with IV contrast can be used for PET attenuation without reducing the clinical value of the PET scan.

METHODS

A uniform phantom study was used to document that the PET acquisition itself is not significantly influenced by the presence of IV contrast medium. Then, 19 patients referred to PET/CT with IV contrast underwent CT scans without, and then with contrast agent, followed by an 18F-fluorodeoxyglucose whole-body PET scan. The CT examinations were performed with identical parameters on a GE Discovery LS scanner. The PET data were reconstructed with attenuation correction based on the two CT data sets. A global comparison of standard uptake value (SUV) was performed, and SUVs in tumour, in non-tumour tissue and in the subclavian vein were calculated. Clinical evaluation of the number and location of lesions on all PET/CT scans was performed twice, blinded and in a different random order, by two independent nuclear medicine specialists.

RESULTS

In all patients, the measured global SUV of PET images based on CT with IV contrast agent was higher than the global activity using non-contrast correction. The overall increase in the mean SUV (for two different conversion tables tested) was 4.5+/-2.3% and 1.6+/-0.5%, respectively. In 11/19 patients, focal uptake was identified corresponding to malignant tumours. Eight out of 11 tumours showed an increased SUVmax (2.9+/-3.1%) on the PET images reconstructed using IV contrast. The clinical evaluation performed by the two specialists comparing contrast and non-contrast CT attenuated PET images showed weighted kappa values of 0.92 (doctor A) and 0.82 (doctor B). No contrast-introduced artefacts were found.

CONCLUSION

This study demonstrates that CT scans with IV contrast agent can be used for attenuation correction of the PET data in combined modality PET/CT scanning, without changing the clinical diagnostic interpretation.

Cytotoxic effects of ionic high-osmolar, nonionic monomeric, and nonionic iso-osmolar dimeric iodinated contrast media on renal tubular cells in vitro

PURPOSE

To compare the cytotoxic effects of dimeric and monomeric iodinated contrast media on renal tubular cells in vitro with regard to osmolality.

MATERIALS AND METHODS

LLC-PK1 cells were incubated with ioxithalamate, ioversol, iomeprol-300, iomeprol-150, iodixanol, iotrolan, and hyperosmolar mannitol solutions for 1-24 hours at concentrations from 18.75 to 150 mg of iodine per milliliter. Cytotoxic effects were assessed with 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Data were analyzed with one-way analysis of variance; post hoc tests were performed.

RESULTS

At equal iodine concentrations, ioxithalamate showed stronger cytotoxic effects than did other contrast media (MTT conversion for ioxithalamate was 4% vs that for ioversol of 32%, that for iomeprol-300 of 34%, that for iodixanol of 40%, and that for iotrolan of 41% of undamaged control cells at 75 mg of iodine per milliliter, n = 61-90, P < .001); there was no significant difference between low-osmolar monomeric and iso-osmolar dimeric contrast media (P > .05). At equal molarity, dimeric contrast media induced significantly stronger cytotoxic effects than did low-osmolar monomeric contrast media (40% for iodixanol and 41% for iotrolan vs 64% for ioversol and 59% for iomeprol-300 at 98.5 mmol/L, n = 61-75, P < .001). At equimolar concentrations, both dimeric contrast media showed stronger cytotoxic effects than did iso-osmolar formulation of iomeprol-150 (51% for iodixanol and 50% for iotrolan vs 77% for iomeprol-150 at 98.5 mmol/L, n = 35-40, P < .001). Mannitol solutions induced weaker cytotoxic effects than did corresponding contrast media compounds (74% for mannitol-520 vs 34% for iomeprol-300 and 41% for mannitol-1860 vs 4% for ioxithalamate, P < .001).

CONCLUSION

Besides hyperosmolality, direct cytotoxic effects of contrast media molecules contribute to their cytotoxic effects. Results of this study indicate that dimeric contrast media molecules have a greater potential for cytotoxic effects on proximal renal tubular cells in vitro than do monomeric contrast media molecules.

CT features of the accessory spleen

OBJECTIVE

The purpose of this study was to describe the prevalence and CT features of the accessory spleen.

CONCLUSION

Accessory spleens are present in 16% of patients undergoing contrast-enhanced abdominal CT. Typically, accessory spleens appear on CT scans as well-marginated, round masses that are smaller than 2 cm and enhance homogeneously on contrast-enhanced images. When accessory spleens are smaller than 1 cm, their attenuation may be lower than that of the spleen because of partial volume effects. Their most frequent location (22%) is posteromedial to the spleen; anterolateral to the upper pole of the left kidney; and lateral, posterior, and superior to the tail of the pancreas. Familiarity with these characteristic features may differentiate them from other pathologic findings in the upper abdomen.

[Methods for the quantification of left ventricular volumes assessed by radionuclide ventriculography (first part)]

The purpose of this study was to point out the existing methods and to describe and evaluate the accuracy of new, original, "Geometric-count-based" (GCB) method, based on radionuclide ventriculography, for the measurement of left ventricular volumes compaired to the contrast ventriculography. By having done this, the aim was to compare the accuracy of GCB method and other two radionuclide methods available for left ventricular volume measurements: Count-bases Massardo method and gated blood pool SPECT method. In GCB method count based data from radionuclide ventriculography were combined with geometric ones assuming a prolate ellipsoid left ventricular's shape with identical short axes. The following equation for computing left ventricular end-diastolic volume was developed: EDV = 2 x c x M x C(tot)/C(max), (1) where: 2c--manually drown short axis of prolate ellipsoid (left ventricle) at end-diastolic frame, M-calibrated pixel size, C(tot)--total counts in left ventricular's region of interest at end-diastolic frame, C(max)--maximum pixel counts in left ventricular's region of interest. Physical experiments with two different heart shaped phantoms were used to compare volumes assessed by all three radionuclide methods with the true volumes. The true volumes of cylindrical and ellipsoid phantoms of 112.5 ml and 190.5 ml, were computed to be 114 ml and 196 ml by our GCB method, 168 ml and 180 ml by Massardo method and 142 ml and 222 ml by gated blood pool SPECT methods, respectively. In clinical study, in 65 patients volumes assessed by radionuclide methods were compared to volumes measured using single plane contrast ventriculography as a gold standard. A good correlation of our original method was obtained with a contrast ventriculography for both EDV/m2 and ESV/m2 (r = 0.94, r = 0.92), slightly lower for Massardo method (EDV/m2: r = 0.90, ESV/m2 : r = 0.89) and significantly lower for gated blood pool SPECT (EDV/m2: r = 0.85, ESV/m2: r = 0.81, p < 0.01). In conclusion, both, phantom and clinical studies indicate that GCB radionuclide method is accurate, noninvasive for left ventricular volumes' measurement and should be widely used in everyday clinical practice.

Sensitivity variation of doped Fricke gel irradiated with monochromatic synchrotron X rays between 33.5 and 80 keV

An experimental binary radiotherapy proposes the concomitant use of a high-Z compound and synchrotron X rays for enhancing radiation dose selectively in tumours by a photoelectric effect. This study aimed at measuring the resulting dose enhancement in irradiated material. A doped Fricke gel dosemeter model was manufactured with 10 mg ml(-1) of iodine (Telebrix) or barium (Micropaque). Samples were irradiated with a monochromatic synchrotron beam at 33.5, 50, 65 and 80 keV. The ensuing enhancement of the sensitivity of the dosemeter was derived from the nuclear magnetic resonance relaxation rates measured at different X-ray doses. Our results demonstrate (1) the preservation of a linear relationship between relaxation rates and X-ray doses for dosemeters doped with high-Z atoms and (2) a clear energy-dependent sensitivity enhancement for barium-doped Fricke gels. This enhancement was neither reproducible with iodinated compounds nor clearly related to the expected dose enhancement factor. However 1% barium sulphate in the gel could significantly improve the gel's response when it was irradiated by low-energy X rays.

Detecting specific cytotoxic T lymphocytes against SARS-coronavirus with DimerX HLA-A2:Ig fusion protein

To assess specific cytotoxic T lymphocytes (CTLs) against Severe acute respiratory syndrome (SARS)-coronavirus, a modified DimerX flow cytometry assay was performed with peripheral blood mononuclear cell (PBMC) from HLA-A2⁺ SARS-recovered donors at different time points post disease. CD8⁺DimerX-S1203⁺ CTLs were detected in the PBMC from these donors up to 3 months after recovery. The percentages of CD8⁺DimerX-S1203⁺ cells paralleled the numbers of interferon-γ-positive spots in an ELISPOT assay using the same antigenic peptide. In conclusion, DimerX-based flow cytometry staining may prove to be a real-time method to screen for CTL directed at epitopes from a newly identified virus.

Evaluation of the nitric oxide production in rat renal artery smooth muscle cells culture exposed to radiocontrast agents

BACKGROUND

Radiocontrast agents (RC), substances largely used in diagnostic procedures, present the nephrotoxicity as one of its major side effects, which could be due to an altered synthesis of vasodilators. The aim of the present study was to evaluate the nitric oxide (NO) production in rat renal artery smooth muscle cells primary culture (rVSMC) exposed to RC.

METHODS

The cells were treated for 72 hours with mannitol at 10% (MT10; 600 mOsm/kg H2O) or 35% (MT35; 2100 mOsm/kg H2O), with the nonionic iobitridol (IBT), the low-osmolality ioxaglate (IXG), the high-osmolality ioxitalamate (IXT), the nonionic, iso-osmolar iodixanol (IDX), and with lipopolysaccharide (LPS). We determined the NO and osmolality in the cell culture media and the cellular viability.

RESULTS

By the Griess and chemiluminescence methods, the NO was not different in MT10 and IDX, but decreased in MT35, IBT, IXG, and IXT when compared with the control; it was increased in LPS and also decreased in all RC+LPS when compared with LPS. MT35, IXT, and IXT+LPS decreased the cellular viability, and the media osmolality was increased in MT35 and IXT compared with the control.

CONCLUSION

The RC (except IDX) significantly reduced NO in rVSMC, which was more pronounced after IXT treatment (57.3%). This was not related to the reduced cell viability (15.8%) or to its high osmolality, because in MT35, with similar osmolality as IXT, NO decreased only 11.0% relatively to the control. Neither the media osmolality nor the cell viability was altered by IXG or IBT. The decreased NO could explain the vasoconstriction and, therefore, the acute renal failure by RC.

Gastrointestinal complications in the neutropenic patient: characterization and differentiation with abdominal CT

PURPOSE

To characterize the computed tomographic (CT) findings of gastrointestinal complications in neutropenic patients and to identify CT features that can help differentiate these complications.

MATERIALS AND METHODS

Abdominal CT scans obtained during a 6-year period were reviewed retrospectively to identify 76 neutropenic patients with radiologic bowel abnormalities. Scans were analyzed for wall thickening, pneumatosis, wall nodularity, mucosal enhancement, bowel dilatation, ascites, and mesenteric stranding. The location and extent of abnormalities were noted. Independent chart and pathology report reviews were used to determine the patients' final diagnoses: neutropenic enterocolitis (n = 53), Clostridium difficile colitis (n = 14), graft-versus-host disease (n = 7), cytomegaloviral colitis (n = 1), and ischemic bowel (n = 1). Results were assessed with the Student t test for quantitative wall thickness and the chi2 test for the number of patients with each diagnosis who demonstrated each CT finding.

RESULTS

Mean bowel wall thickening was greatest in C difficile colitis (12 mm) and least in graft-versus-host disease (5 mm). Pneumatosis was limited to neutropenic enterocolitis (21% [11 of 53 patients]) and bowel ischemia. Wall nodularity was significantly more common (P <.01) in C difficile colitis (36% [five of 14 patients]). In graft-versus-host disease, the rates of mucosal enhancement and bowel dilatation were highest (P <.05) (71% [five of seven patients] and 86% [six of seven patients], respectively). In C difficile colitis, the rates of ascites and mesenteric stranding were highest (57% [eight of 14 patients] and 71% [10 of 14 patients], respectively). Although findings in neutropenic enterocolitis and graft-versus-host disease could involve any bowel segment, C difficile colitis was always limited to the colon.

CONCLUSION

Several CT findings can help differentiate specific gastrointestinal complications in neutropenic patients.

Inadvertent intrathecal use of ionic contrast agent

Intrathecal administration of ionic contrast media may cause severe and fatal neurotoxic reactions due to their hyperosmolarity and ionic nature. They are therefore strictly contraindicated for all radiologic applications involving the central nervous system (e.g., myelography). We present a case in which ioxitalamate was accidentally injected intrathecally. The patient recovered completely due to a combination of the different therapeutic options reported in the literature, including early mechanical ventilation and neuromuscular paralysis, aggressive control of seizures, elevation of head and trunk to prevent cephalad migration of contrast, steroids, cerebrospinal fluid drainage and lavage and prophylactic antibiotics.

[Comparison of iodinated and barium-containing contrast media of different viscosity in the detection of pharyngeal perforation]

PURPOSE

In contrast to esophageal perforations, the more radiopaque barium-suspensions are not as important as iodinated aqueous contrast agents for the detection of pharyngeal perforations. This study was performed to find out whether the highly different viscosities (of iodinated and barium-containing contrast agents with comparable radiopacities) are a reason for this.

METHODS

Viscosity, subjective difference in contrast, and CT-density of an iodinated aqueous (Telebrix) and a 50 wt/vol% barium-containing contrast agent (Micropaque) were determined. Moreover, to exclude postoperative perforation, 104 patients were prospectively examined by pharyngography using both contrast media. Pharyngographies of patients with perforation were later compared by two independent readers. All patients with perforation were followed up clinically to exclude complications due to barium administration.

RESULTS

In-vitro comparison showed comparable radiopacity but the 50 wt/vol% barium-suspension was much more viscous than the iodinated contrast agent. During pharyngography, totally, 14 perforations were clearly delineated with the iodinated aqueous contrast agent. However, two of them were not detected with the barium-suspension. All the other perforations presented equally.

CONCLUSIONS

Given a sufficient radiopacity, a low viscosity appears to be essential for a contrast agent to detect especially pharyngeal perforations. Thus, we recommend the sole use of an iodinated contrast agent (at suspicion of aspiration as isoosmolar variant) for this purpose.

Ionic and non-ionic contrast agent-mediated endothelial injury. Quantitative analysis of cell proliferation during endothelial repair

PURPOSE

To quantitatively evaluate endothelial injury in vivo and to assess the time course of cellular repair after endothelial cell exposure to ionic and non-ionic contrast media.

MATERIAL AND METHODS

Local changes at the cellular level following intraaortic injection of 1 ml of the ionic contrast agent ioxithalamate or 1 ml of the non-ionic contrast agent iomeprol, each with an iodine content of 300 mg/ml, were investigated using rat endothelium as an in vivo model. A sorbitol solution iso-osmolar to iomeprol served as control. Quantitative analysis of endothelial changes by autoradiography of 3H-thymidine-labeled endothelial cells was assessed after 3, 5 and 10 days, determining the 3H-thymidine index and the DNA synthesis rate.

RESULTS

Ioxithalamate showed a clear harmful effect on the endothelium, with an elevated 3H-thymidine index of 7.68% on day 3 and 6.89% on day 5, versus 2.97% on day 3 and 2.55% on day 5 for iomeprol and 2.29% on day 3 and 1.91% on day 5 for the control.

CONCLUSION

Ionic contrast agents lead to reversible transient focal endothelial cell injury. No such side effect was detectable for non-ionic contrast agents.

Detection of pharyngeal perforation: comparison of aqueous and barium-containing contrast agents

OBJECTIVE

We sought to assess the value of aqueous and barium-containing contrast agents in the detection of pharyngeal perforation.

SUBJECTS AND METHODS

Visual and objective in vitro comparisons of an iodinated aqueous contrast agent, a 50% weight/volume barium suspension, and a 100% weight/volume barium suspension were performed. Moreover, to exclude pharyngeal perforation after surgery, we prospectively examined 109 patients by pharyngography, using the aqueous contrast agent and the 100% weight/volume barium suspension. All patients with a pharyngeal perforation were followed up clinically to exclude complications due to barium application.

RESULTS

As opposed to the 100% weight/volume barium suspension, in vitro comparison between the aqueous contrast agent and the 50% weight/volume barium suspension yielded no substantial differences. Seventeen perforations could be detected with the aqueous contrast agent. Although 10 of 17 perforations could be slightly better visualized with the 100% weight/volume barium suspension, two perforations were missed with this agent. Five perforations were equally well detected with both.

CONCLUSION

Because of a higher radiopacity, 100% weight/volume barium suspensions may more sharply delineate perforations. However, in contrast to aqueous contrast media, narrow pharyngeal perforations can be missed. Thus, the use of a 100% weight/volume barium suspension does not improve the detection of pharyngeal perforation.

Ejaculatory duct obstruction: TRUS-guided opacification of seminal tracts

OBJECTIVE

To assess the usefulness of TRUS-guided aspiration and opacification of seminal tracts in the evaluation and management of patients with ejaculatory duct obstruction (EDO).

METHODS

In 21 men who had dilated seminal vesicles and/or midline cysts on TRUS, a mixture of contrast media and indigocarmine was injected and then pelvic radiographs were taken.

RESULTS

The diagnoses based on the findings of TRUS-guided opacification were bilateral EDO in 9 patients, unilateral EDO in 1, and midline cyst with EDO in 11. Midline cysts had communication with seminal tracts in 7. Transurethral unroofing was performed in 12, in all of whom blue color of the injected indigocarmine facilitated the surgical procedure.

CONCLUSION

TRUS-guided opacification of the seminal tracts with a mixture of contrast media and indigocarmine may be valuable in the evaluation and management of the patients with EDO.

Intestinal malrotation as an incidental finding on CT in adults

BACKGROUND

Intestinal malrotation in adults is usually an incidental finding on computed tomography (CT). We present the CT findings of 18 adult patients with malrotation and discuss the clinical implications.

METHODS

Abdominal scans of 18 patients (12 women, six men; age range = 15-79 years) with intestinal malrotation were reviewed. Special attention was directed to the location of the superior mesenteric vessels, the location of the small and large bowels, the size of the uncinate process, the situs definition, and additional anomalies.

RESULTS

The malrotation was an incidental finding in all but one patient. The malrotation was type Ia in 17 patients and IIc in the one symptomatic patient. The superior mesenteric vessels were vertically oriented in 10, inverted in two, normally positioned in four, and mirror imaged in two cases with situs ambiguus. All patients had aplasia of the pancreatic uncinate process, five had a short pancreas, and two had a preduodenal portal vein. Fourteen patients had a normal situs and four had heterotaxia. Seven patients had polysplenia, six of which with associated inferior vena cava anomalies.

CONCLUSIONS

Intestinal malrotation can be diagnosed on CT by the anatomic location of a right-sided small bowel, left-sided colon, an abnormal relationship of the superior mesenteric vessels, and aplasia of the uncinate process. Awareness of these abnormalities is necessary to diagnose this anomaly. It should be sought in patients with a situs problem, inferior vena cava anomalies, polysplenia, or preduodenal portal vein. Although usually an incidental finding, it is important to diagnose such a malrotation because it may cause abdominal symptoms. Also, knowledge of associated vascular anomalies is important when abdominal surgery is planned.

Proximal arterioportal shunting associated with hepatocellular carcinoma: features revealed by dynamic helical CT

OBJECTIVE

This study investigated the findings revealed by dynamic helical CT of proximal arterioportal shunting associated with hepatocellular carcinoma. We also evaluated the diagnostic capability of this imaging technique to reveal the mass in patients with hepatocellular carcinoma.

CONCLUSION

On dynamic helical CT, proximal arterioportal shunting altered liver perfusion and tumor enhancement. Heterogeneous enhancement of liver parenchyma and decreased enhancement of hepatomas diminished diagnostic capability on the arterial dominant phase image. However, with the addition of imaging in the arterial portal phase, lesion conspicuity improved.

Cranial CT revisited: do we really need contrast enhancement?

The aim of this study was to define guidelines for intravenous contrast administration in cranial CT, as currently there are no recent guidelines based on a large series of patients. In 1900 consecutive patients (1480 adults and 420 children) pre- and post-contrast scan was analysed in order to assess the contribution of contrast enhancement to the diagnosis. The findings were grouped according to whether abnormalities were seen on the pre- and/or post-contrast scan, or whether no abnormalities were seen at all. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of a pre-contrast scan were used to determine validity. Intravenous contrast enhancement only contributes to the diagnosis if a suspicious abnormality is seen on the unenhanced scan or in the appropriate clinical setting (33.6%). In the remaining patients (65.6%) there is no diagnostic contribution, except for a small number of abnormalities (0.8%). These are often anatomical variants and have no therapeutic impact. The number of contrast-enhanced cranial CT examinations can significantly be reduced by using four general guidelines for contrast administration resulting in considerable cost savings without affecting the quality of service to the patient. These guidelines are defined by the clinical findings/presentation or by the findings on the unenhanced scan. The number of contrast-related complications will be reduced, which may have medicolegal implications. These guidelines can be applied in any radiology department.

CT diagnosis of non-traumatic subarachnoid haemorrhage in patients with brain edema

The aim of the study is to prove, retrospectively, that it is unlikely that the computerized tomography (CT) diagnosis of subarachnoid haemorrhage (SH) accompanies the CT diagnosis of generalized brain edema. A total of 100 comatose patients underwent CT of the brain. Of this number, 42 underwent an enhanced CT scan. In 26 patients, lumbar puncture was also performed. A control group of ten patients diagnosed with headache and having a normal CT scan underwent NECT and ECT. Measurements of the white and gray matter density in Hounsfield units (HU) were performed in all 110 cases, including the controls. The brain tissue density and the difference between the densities of the white and gray matter were lower in the cases with brain edema than in the controls. The data values were statistically significant. Small cerebral ventricles, sulci and cisterns and small differences between white and gray matter measurements were observed in the CT scans of the brain edema cases. All 100 patients had CT diagnosis of brain edema and SH. There was no bloody or xanthochromic CSF in any of the 26 lumbar punctures performed. In the enhanced CT scans, there was poor or no filling of the lateral sinuses. The compression of the lateral sinuses by the edematous brain tissue most probably results in their stenosis or obstruction due to disturbed brain venous drainage which can mimic CT findings of SH.

Similar cytogenetic effects of sodium-meglumine diatrizoate and sodium-meglumine ioxithalamate in lymphocytes of patients undergoing brain CT scan

Cytogenetic effects of two ionic contrast media (CM), Urografin 76% a sodium-meglumine diatrizoate, and Telebrix 38, a sodium-meglumine ioxythalamate, were tested on lymphocytes of patients undergoing brain CT Scan. Both compounds have approximately similar iodine concentrations. Chromosomal aberrations were scored in peripheral lymphocytes obtained from 15 patients undergoing brain CT with either urografin 76% or telebrix 38 before and after examination. Results showed no difference in aberration frequency for patients who underwent brain CT without contrast materials compared to controls. However, injection of CM resulted in a high frequency of chromosomal aberrations which significantly differed from controls (P < 0.05). The effect of urografin 76% appeared to be similar to telebrix 38. Therefore, both CM exhibited clastogenic effects on peripheral lymphocytes in vivo. An increase in chromosomal aberrations due to CM used in this study were similar to that reported for other ionic and non-ionic compounds.

CT of the mesenteric vascular anatomy

BACKGROUND

To evaluate the appearance of the arrangement of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) on computed tomography (CT) in normal patients and in patients with abdominal masses.

METHODS

One hundred seventy-seven consecutive abdominal CT examinations of 143 adults and two children were reviewed. The relationship of the SMV to the SMA was recorded at four locations: the beginning of the mesenteric vessels and levels 3 cm, 6 cm, and 9 cm caudad to the beginning. The relationship of the SMV to the SMA was divided into four quadrants in relation to the SMA: I, ventral right or directly ventral; II, dorsal right or directly right; III, dorsal left or directly dorsal; and IV, ventral left or directly left.

RESULTS

In the beginning of the SMV-SMA complex and levels 3 cm, 6 cm, and 9 cm caudal to the beginning, the SMV was located in quadrant I in 146, 84, 69, and 43 examinations, in quadrant II in 31, 93, 71, and 27 examinations, in quadrant III in zero, zero, five, and three examinations, and in quadrant IV in zero, zero, nine, and 15 examinations, respectively. The cases with SMV inversion had neither malrotation nor adjacent tumor compression. All the cases with an adjacent tumor-induced compression of the SMV-SMA complex had a normal SMV-SMA relationship.

CONCLUSION

In the first 3 cm, the SMV is always to the right of the SMA. Caudal to the level of 6 cm, the SMV may be located to the left of the SMA without evidence of malrotation. A midgut nonrotation is more likely to be present when a proximal SMV inversion is coexistent with a rightward direction of the proximal jejunal vessels. A hypothetical depiction of the step-by-step change of the SMV-SMA relationship during embryologic development may explain the arrangement patterns of the mesenteric vessels in normal rotation and midgut nonrotation.

Peripheral cholangiocarcinoma of the liver: two-phase spiral CT findings

PURPOSE

To determine characteristic features of peripheral cholangiocarcinoma on two-phase spiral computed tomographic (CT) scans.

MATERIALS AND METHODS

Thirty-four patients with peripheral cholangiocarcinoma underwent two-phase spiral CT. Hepatic arterial phase and portal venous phase images were obtained 30 and 65 seconds, respectively, after the start of contrast material infusion.

RESULTS

Thin, mild, incomplete rimlike contrast enhancement at the tumor periphery was seen on CT scans from both phases in 23 patients. Thick, continuous rimlike contrast enhancement and marked homogeneous contrast enhancement were present on scans in four patients and one patient, respectively. No definite contrast enhancement pattern was seen on scans in six patients. Other findings included increased lobar or segmental hepatic attenuation in adjacent normal liver during the arterial phase (n = 10), markedly low attenuation with amorphous areas of slightly high attenuation in the tumor during both phases (n = 33), internal septumlike linear structures (n = 8), narrowing or obstruction of the portal vein as it traversed the tumor (n = 16), and a patent hepatic vein (n = 4).

CONCLUSION

Thin, mild, incomplete rimlike contrast enhancement at the tumor periphery and markedly low intratumoral attenuation with amorphous areas of slightly high attenuation during both scanning phases are typical findings of peripheral cholangiocarcinoma.

Esophageal perforation: comparison of use of aqueous and barium-containing contrast media

PURPOSE

To assess the need for follow-up esophagography with barium-containing contrast medium after examination with a water-soluble contrast medium in the detection of esophageal perforation.

MATERIALS AND METHODS

Sixty-seven patients suspected of having esophageal perforation were examined prospectively with use of an aqueous contrast medium during a 1-year period. The examinations were performed with a digital fluoroscopy unit. Eighteen patients without proved extravasation at esophagography performed with aqueous contrast medium and without other contraindications underwent esophagography with barium-containing contrast medium.

RESULTS

In four of 18 patients (22%) with unremarkable findings at esophagography performed with a water-soluble contrast medium, a perforation was detected subsequently with use of a barium-containing contrast medium. No complications related to barium extravasation occurred.

CONCLUSION

Patients suspected of having esophageal perforation and who have unremarkable findings at esophagography with water-soluble contrast media need to undergo follow-up esophagography with a barium-containing contrast medium. The use of a digital fluoroscopy unit does not obviate the follow-up examination.

Functioning islet cell tumor of the pancreas. Localization with dynamic spiral CT

PURPOSE

The purpose of this study was to evaluate the usefulness of dynamic spiral CT, including multidimensional reformation, in the detection and localization of islet cell tumors of the pancreas.

MATERIAL AND METHODS

Seven patients with histopathologically proven functioning islet cell tumors of the pancreas were studied with 2-phase contrast-enhanced spiral CT. Scanning of the arterial phase and late phase was started 30 s and 180 s, respectively, after injection of 100 ml of contrast medium at a rate of 3 ml/s.

RESULTS

Axial images in the arterial phase depicted the lesions in 5 patients, but in the late phase in only one patient. Multiplanar reformatted images of the arterial phase depicted the lesions in all 7 patients. Maximal intensity projection images demonstrated all lesions with information of their relationship to the vascular structure.

CONCLUSION

Dynamic spiral CT with scanning during the arterial phase and retrospective multidimensional reformation is useful for preoperative detection and localization of small islet cell tumors of the pancreas.

Detection of hypervascular nodular hepatocellular carcinomas: value of triphasic helical CT compared with iodized-oil CT

OBJECTIVE

The objective of this study was to compare the capability of arterial, portal venous, and delayed phases of helical CT with that of iodized-oil CT for revealing nodular hepatocellular carcinomas.

MATERIALS AND METHODS

Forty-eight patients with nodular hepatocellular carcinomas underwent triphasic helical CT examination with 10-mm collimation at 10-mm/sec table speed. We injected 120 ml of contrast material (36 g of iodine) at the rate of 3 ml/sec. Arterial-phase, portal venous-phase, and delayed-phase images were obtained with 30-sec, 65-sec, and 360-sec delays, respectively. All 48 patients also underwent angiography and intraarterial infusion of iodized oil after helical CT; iodized-oil CT was performed about 2 weeks after infusion of iodized oil. Helical CT images were compared with iodized-oil CT images for revealing hepatic nodules.

RESULTS

In 48 patients, 79 hepatocellular carcinomas were seen with iodized-oil CT. Using helical CT, the arterial phase revealed 68 lesions (86%), the portal venous phase revealed 53 lesions (67%), and the delayed phase revealed 57 lesions (72%). The arterial phase proved superior to the portal venous and delayed phases for revealing lesions (p = .0025). The portal venous phase showed no significant difference for revealing lesions compared with the delayed phase. When combined, helical CT of the arterial and portal venous phases revealed 73 lesions (92%); a combination of the arterial and delayed phases revealed 72 lesions (91%); and a combination of the portal venous and delayed phases revealed 63 lesions (80%). Any combination of two phases that included the arterial phase proved superior to the combination of the portal venous and delayed phases (p = .0033). Overall, the combination of the arterial and portal venous phases (92%) or the combination of all three phases (92%) proved best at revealing lesions.

CONCLUSION

The arterial phase of helical CT is better for revealing nodular hypervascular hepatocellular carcinoma than are the portal venous and delayed phases. The combination of the arterial and portal venous phases is superior to the arterial phase alone. Also, the combination of the arterial and portal venous phases is equal to the combination of the three phases for revealing hypervascular hepatocellular carcinomas.

Meglumine gadoterate: a new safe radiocontrast medium for endoscopic retrograde cholangiopancreatography?

The radiocontrast substance meglumine gadoterate (MG) is used in magnetic resonance imaging. It is characterized by its low rate of adverse drug reactions. In an open study we tested whether MG is useful in endoscopic retrograde cholangiopancreatography. The patients received in sequence MG and ioxotalamate. MG, in contrast to ioxotalamate, failed to visualize the proximal pancreatic and peripheral intrahepatic ducts. Thus, MG is not useful in routine endoscopic retrograde cholangiopancreatography. However, in patients with a history of severe allergic reactions to conventional contrast media, MG may be recommended when pathological findings of the extrahepatic bile duct or the area of the pancreatic head are suspected.

Lung cancer in patients with idiopathic pulmonary fibrosis: CT findings

PURPOSE

The frequency of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) is higher than that of general population. To evaluate CT findings of lung cancer associated with IPF, we analyzed 32 patients with lung cancer associated with IPF.

METHOD

We analyzed retrospectively 32 patients with histologically confirmed lung cancer out of 244 consecutive cases diagnosed as IPF by either CT and clinical findings (n = 220) or histologically (n = 24). The patients were 40-85 years old (mean 66 years, M/F = 31/1). Scanning techniques were conventional CT in 24 patients, high-resolution CT (HRCT) in 2 patients, and both conventional CT and HRCT in 6 patients. We analyzed the CT patterns, locations, and histologic types of lung cancer.

RESULTS

The frequency of lung cancer in patients with IPF was 13.1% (32/244). In 17 of 32 patients, the CT findings of lung cancer were ill defined lesions mimicking air-space consolidation. Lung cancer was located mainly in the lower lobes (21/32) and peripheral portion (21/32). Histologically, squamous cell carcinoma was the most common type (18/32).

CONCLUSION

Typical CT findings of lung cancer were ill defined consolidation-like masses at the peripheral portion where the most advanced fibrosis was located.

Helical CT anatomy of pancreatic arteries

BACKGROUND

To assess the frequency of visualization of pancreatic arteries in the arterial phase of helical computed tomography (CT).

METHODS

The visibility of pancreatic and peripancreatic arteries in helical CT images was evaluated in 20 consecutive patients who had no evidence of pancreatic disease. CT examinations were performed by using a continuously rotating CT scanner and intravenous injection of contrast media. The scans were taken 35 s after the start of injection and with a table speed of 3 mm/s. Images were reconstructed in 3-mm section increments.

RESULTS

Frequently visualized arteries were the gastroduodenal, anterior and posterior superior pancreaticoduodenal, and right gastroepiploic arteries. Infrequently visualized arteries were the dorsal pancreatic, pancreatica magna, caudal pancreatic, transverse pancreatic, and common, anterior, and posterior inferior pancreaticoduodenal arteries.

CONCLUSION

Helical CT enabled us to recognize small pancreatic arteries, and the evaluation of these arteries should be considered in the staging of pancreatic carcinoma.

Blunt hepatic trauma in adults: correlation of CT injury grading with outcome

PURPOSE

To correlate injury grading with computed tomography (CT) to treatment outcome.

MATERIALS AND METHODS

Forty-eight patients with proved blunt hepatic injuries underwent dynamic CT with contrast material before treatment. The injuries were classified with a five-point CT-based grading system. The CT injury grades and the amount of hemoperitoneum seen on CT scans were compared with the clinical and surgical findings, radiologic follow-up, and outcome.

RESULTS

Hepatic injuries were classified as CT grade 1 in two patients, grade 2 in 15 patients, grade 3 in 21 patients, and grade 4 in 10 patients. Conservative treatment was performed in 38 patients, including 15 patients with grade 3 and 10 patients with grade 4 injuries; 10 of these patients also had major hemoperitoneum (> 500 mL). Conservative treatment was successful in 37 patients but was complicated in two patients by development of an arteriovenous fistula or a biloma and failed in one patient because of delayed hepatic rupture. Exploratory laparotomy was performed in 10 patients but revealed marked active hepatic bleeding in only one patient.

CONCLUSION

Injury grading with CT may reflect the degree of hepatic parenchymal damage but does not indicate patients in whom complications may develop or surgery is necessary. Monitoring of conservative treatment with CT allows detection of resultant complications.

Nonsurgical placement of a nasolacrimal polyurethane stent: long-term effectiveness

PURPOSE

To evaluate the long-term effectiveness of a polyurethane stent in the treatment of obstruction of the lacrimal sac and the nasolacrimal duct.

MATERIALS AND METHODS

Fluoroscopically guided placement of a polyurethane nasolacrimal stent was evaluated in 283 obstructed lacrimal systems of 236 patients, with a follow-up period of more than 1 year (range, 52-134 weeks). The obstruction was at the junction between the lacrimal sac and the nasolacrimal duct in 192 systems, at the lacrimal sac in 52, and at the nasolacrimal duct in 39. The causes of obstruction were traumatic in 34 and idiopathic in 249 systems.

RESULTS

Stent placement was technically successful in 270 systems (95%). At 7 days after stent placement, 235 (87%) of the 270 systems with successful placement demonstrated complete resolution of epiphora, 27 (10%) had partial resolution, and the remaining eight (3%) had no resolution. There was recurrence in 81 systems due to obstruction of the stent (n = 77) or obstruction of the common canaliculus (n = 4). The recurrence rate was much higher in the systems with obstruction at the lacrimal sac (64%) than in the systems with obstruction at the junction (26%) between the lacrimal sac and nasolacrimal duct or at the nasolacrimal duct (15%).

CONCLUSION

Stent placement in the obstructed lacrimal system below the junction between the lacrimal sac and the nasolacrimal duct is valuable as an initial therapy.

Spiral CT for the detection of hepatocellular carcinomas:relative value of arterial- and late-phase scanning

BACKGROUND

Spiral computed tomography (CT) can image the liver during arterial and late phases of contrast and optimize the evaluation of hypervascular tumor. The objective of this study was to evaluate the relative value of arterial- and late-phase spiral CT in the detection of hepatocellular carcinomas.

METHODS

Fifty-eight patients with hepatocellular carcinomas underwent two-phase spiral CT examination with 10-mm collimation at 10 mm/s table speed (Siemens Somatom Plus S), and 120 mL of contrast material (36 g iodine) was injected at the rate of 3 mL/s. CT images of hepatic arterial and late phases were obtained with a 35-s and 180-s delay, respectively.

RESULTS

In 58 patients, 111 hepatocellular carcinoma lesions were seen. The arterial phase detected 93 (84%) and the late phase 75 (68%) lesions (p < 0.01). The arterial phase detected more lesions in 11 patients, and the late phase detected more in two patients and an equal number in 45 patients. If lesions larger than 2 cm are excluded, the arterial phase detected 40 (74%) and the late phase 21 (39%) of 54 lesions (p < 0.001).

CONCLUSION

The arterial phase of spiral CT greatly improves the detection of hepatocellular carcinoma when compared with the late phase.

Contrast-enhanced CT: value for diagnosing local breast cancer recurrence after conservative treatment

PURPOSE

To assess contrast material-enhanced computed tomography (CT) of breast for diagnosing local recurrence after conservative therapy.

MATERIALS AND METHODS

In 111 patients, 118 lesions were evaluated with unenhanced and enhanced CT. Criterion for cancer recurrence was detection of a lesion with an enhancement of 45 HU or more.

RESULTS

One group comprised 52 lesions with pathologic diagnoses, obtained within 1 month of CT, of malignancy in 43 and benignancy in nine. Scans were positive in 40 of 43 recurrences and negative in six of nine benign lesions. Seventeen recurrent lesions were nonpalpable, and contrast-enhanced CT results were true-positive in 15 of these. A second group comprised 66 lesions with a mean follow-up of the treated breast of 28 months after CT. In 56 lesions, the scans were negative, with no recurrence in 55; local recurrence was proved with a 14-month delayed surgical biopsy in one. In 10 lesions, scans were positive, with a delayed diagnosis of recurrence 5 and 6 months after CT in two and no evidence of recurrence in eight (false-positive results). The sensitivity of breast CT for both groups was 91% (42 of 46 lesions) with a specificity of 85% (61 of 72 lesions).

CONCLUSION

Contrast-enhanced CT is sensitive in the diagnosis of local recurrence of breast cancer, even in nonpalpable lesions, and may be a useful tool in patients with equivocal clinical and/or mammographic findings during follow-up after conservative therapy.

Contrast media are incomplete secretagogues acting on human basophils and mast cells isolated from heart and lung, but not skin tissue

To investigate the mechanisms of anaphylactoid reactions to radiocontrast media, in vitro mediator release induced by three iodinated contrast agents was examined using peripheral blood basophils and mast cells purified from human lung parenchyma, heart, and skin tissues. Three iodinated contrast agents, sodium and meglumine salts of ioxaglic acid, sodium and meglumine salts of ioxithalamic acid, and ioversol, were incubated with basophils purified from peripheral blood and human mast cells isolated and purified from different anatomical sites. Release of preformed (histamine and tryptase) and de novo synthesized mediators (prostaglandin D2 and leukotriene C4) into the supernatans was determined at various contrast medium concentrations after incubation for 60 min. Ioxaglate (0.2-0.3 M), ioxithalamate (0.3-0.5 M), and to a lesser extent ioversol (0.3-0.5 M) induced histamine release from basophils in a concentration-dependent manner. All three induced the release of preformed mediators (histamine and tryptase) from human lung, but not from skin mast cells. They also induced histamine and tryptase release from human heart mast cells. However, they did not induce the de novo synthesis of leukotriene C1 or prostaglandin D2 from human basophils or any type of mast cell examined. Cross-linking of IgE by anti-IgE induced the release of leukotriene C4 or prostaglandin D2 from human basophils or mast cells. Mannitol, an osmotic stimulus, induced the release of histamine from human basophils, but to a lesser extent from mast cells. These results show that different contrast media can differ in their ability to release mediators from enriched preparations of human basophils and mast cells. The three contrast agents examined act on basophils and mast cells as incomplete secretagogues, causing the release of preformed mediators, but not these novo synthesis of chemical mediators. It may be useful to measure plasma tryptase levels to detect adverse reactions caused by iodinated radiographic contrast materials.

Acute mesenteric ischemia: diagnosis with contrast-enhanced CT

PURPOSE

To evaluate the accuracy of dynamic, contrast material-enhanced computed tomography (CT) in the diagnosis of acute mesenteric ischemia.

MATERIALS AND METHODS

Reviewers blinded to patient diagnoses retrospectively compared the CT scans in a study group with those in a control group. The study group comprised 39 consecutive patients (23 men, 16 women; aged 55-88 years) with surgically proved acute mesenteric ischemia. The control group comprised 24 patients (13 men, 11 women; aged 50-82 years) with suspected acute mesenteric ischemia that was disproved at surgery.

RESULTS

For the diagnosis of acute mesenteric ischemia, each of the following findings had a specificity of more than 95% and a sensitivity of less than 30%: arterial or venous thrombosis, intramural gas, portal venous gas, focal lack of bowel-wall enhancement, and liver or splenic infarcts. When CT was used in the diagnosis of suspected acute mesenteric ischemia, the detection of at least one of these signs resulted in a sensitivity of 64% (25 of 39; confidence interval, 0.49, 0.79), a specificity of 92% (22 of 24; confidence interval, 0.81, 1.00), and an accuracy of 75% (47 of 63; confidence interval, 0.64, 0.86).

CONCLUSION

Dynamic, contrast-enhanced CT is a valuable tool in the diagnosis of and determination of prognosis in acute mesenteric ischemia.

Human basophil/mast cell releasability. XI. Heterogeneity of the effects of contrast media on mediator release

BACKGROUND

The activation of basophils and mast cells plays a role in the pathogenesis of anaphylactoid reactions occurring during the administration of iodinated radiocontrast media.

METHODS

We compared the effects of three contrast media (CM), Hexabrix (sodium and meglumine salts of ioxaglic acid), Telebrix (sodium and meglumine salts of ioxitalamic acid), and Optiray (ioversol) on the release of preformed (histamine and tryptase) and de novo synthesized (prostaglandin D2 and leukotriene C4) mediators from human basophils and mast cells isolated from lung, skin, and heart tissue. The commercial preparations were evaluated in parallel with the pure substances. Mannitol was used as a positive control inducing histamine release (HR) by hyperosmolar stimulation.

RESULTS

Hexabrix (0.1 to 0.3 mol/L), Telebrix (0.1 to 0.5 mol/L), Optiray (0.2 to 0.5 mol/L), and the corresponding pure substances concentration-dependently induced HR from basophils. A positive correlation was found between CM osmolality and HR from basophils. Mast cells isolated from different anatomic sites responded differently to the three CM. Hexabrix and Optiray induced histamine and tryptase release from human lung mast cells, but not from human skin mast cells. No correlation was found between the osmolality of CM and HR from human lung mast cells. There was a significant correlation between the percent of histamine and tryptase release induced by CM from human lung mast cells. Hexabrix, Telebrix, and Optiray also induced histamine and tryptase release from human heart mast cells. None of the CM induced the de novo synthesis of leukotriene C4 or prostaglandin D2 from basophils or mast cells. The kinetics of HR caused by CM differed according to the drug used and the cell (basophils or human lung mast cells) examined. CM-induced HR from basophils and human lung mast cells was temperature-dependent, partially influenced by extracellular Ca2+ concentrations, and not modified by preincubation of basophils with IL-2 or IL-3.

CONCLUSIONS

These results provide evidence of the heterogeneity of the effects of CM on mediator release from human basophils and mast cells from different anatomic sites. They also suggest that hyperosmolarity may be an important factor in the activation of basophils by CM, but less relevant for mast cells. CM induce only the release of preformed mediators. The measurement of plasma tryptase might be clinically useful for monitoring adverse reactions caused by CM.