Local and systemic effects of water-soluble contrast media and barium in rats with chronic small bowel obstruction

RATIONALE AND OBJECTIVES: The local effects on the small intestine and systemic changes produced by different contrast media in small bowel obstruction, with time courses of 4 days, were evaluated. MATERIALS AND METHODS: Four groups, each with 10 normal rats and another four groups (also each with 10 rats) that had ligation of the terminal ileum (obstructed rats) for 4 days were given 3 mL of barium, meglumine sodium diatrizoate, iohexol, or saline (control animals). Radiographs were taken immediately, 1 and 4 hours after administration of contrast media. Immediately before sacrifice, blood samples were taken to determine the hematocrit (Hct), hemoglobin (Hb), white blood cell count (WBC), red blood cell count (RBC), and serum sodium, and potassium and chloride concentrations. Specimens of small bowel were taken for histologic and morphometric analysis. RESULTS: In obstructed rats, the image quality with iohexol improved on final radiographs despite being diluted in the great intestinal contents. There was an improvement in the serum electrolyte concentrations in the obstructed animals that were given any one of the contrast media, the best improvement being in the iohexol groups. A shortening of the length of epithelial cells when any one of the contrast media was administered was observed, as was an increase in the lymphatic space area in the diatrizoate group in normal rats. In the bowel proximal to the obstruction, the lymphatic space area was increased in the diatrizoate group and the size of the epithelial cells was higher in the diatrizoate and iohexol groups compared to the barium and saline groups. CONCLUSION: Our results suggest that iohexol offers good radiologic efficacy and excellent systemic and local tolerance in small bowel obstruction.     

Vasorelaxing activity of resveratrol and quercetin in isolated rat aorta

PURPOSE: To assess the severity of adverse reactions to contrast media in outpatient computed tomographic (CT) examinations in a conventional clinical setting. MATERIALS AND METHODS: In 4,936 patients, CT was performed with four protocols: ionic contrast medium with sodium meglumine as the cation (in one protocol, contrast material was warmed to 35 degrees C before injection; in another protocol, it was administered at ambient temperature); warmed, ionic contrast medium with nonsodium pure meglumine as the cation; and warmed, nonionic iopamidol. RESULTS: Adverse reactions to ionic contrast material statistically significantly decreased (P<.05) when it was warmed before administration. Reactions to ionic contrast media without a sodium cation were statistically significantly fewer (P<.001) than reactions to those with a sodium cation. In all protocols, pediatric patients had fewer reactions than adult patients. CONCLUSION: In outpatient CT examinations, nonionic, warmed contrast medium was the best option because no severe reactions resulted from its use. Prevalence of adverse reactions was comparable to that in controlled randomized studies.     

Rate of neuronal fallout in a transsynaptic cerebellar model

PURPOSE: A retrospective study was undertaken of the late adverse reactions following the injection of contrast media. The purpose was to determine whether there was a difference between non-ionic monomeric (iohexol) and non-ionic dimeric (iodixanol) contrast media in the reactions produced. MATERIAL AND METHODS: A total of 3,408 patients were sent a written questionnaire in which they were asked to confirm or deny any subjective discomfort or adverse event during a period of one hour to one week after a previous radiological examination with contrast medium. Patients who had undergone angiography (i.v. or i.a. injection) and CT (i.v. injection) were included. Objective signs of an allergy-like reaction were listed and the patients were asked to subjectively quantify any consequent discomfort. RESULTS: The compliance rate was 84%. Of the 3075 injections finally included in the study, 133 (4.3%) had resulted in contrast-medium-related adverse reactions of which 72 (2.3%) were immediate and 61 (2%) were late. Iohexol induced late reactions in 14/851 (1.7%) cases, and iodixanol in 24/1218 (2.0%) cases following i.v. injection and in 23/1006 (2.3%) cases following i.a. injection. The differences were not significant. There were no differences between the two contrast media in the subjective rating of discomfort except that the patients who had received iodixanol also had the highest individual-intensity score. No patient had been hospitalized owing to an adverse reaction and all reactions had been regarded as mild or moderate. CONCLUSION: The number of late adverse reactions was low. There was no difference in the frequency of the late adverse reactions following i.v. injection between iodixanol and iohexol. There was also no difference in the reactions between the i.a. and i.v. injections of iodixanol.     

Delayed-type hypersensitivity to a nonionic, radiopaque contrast medium

BACKGROUND: True allergic reactions to iodinated radiocontrast media are rare, and only a few well-documented cases of delayed-type hypersensitivity reactions caused by contrast media have been described. METHODS: We report a 61-year-old patient in whom percutaneous transluminal coronary angioplasty (PTCA) was performed with iopamidol, a nonionic contrast medium. Seven days later, the patient developed generalized maculopapular exanthema. Repeated patch tests with several iodinated agents were performed. RESULTS: A first patch test with iopamidol was positive. Repetition of the patch tests showed positive results to iopamidol as well as to iohexol and ioversol, two other nonionic contrast media, but not to other iodinated substances. Three months later, PTCA was repeated, and iopamidol was used again. Despite premedication, pruritic macular exanthema developed 1 day later. Whether iopamidol or trometamol -- an additive substance in the contrast medium -- was causative could not be determined, since a third set of patch tests was negative. CONCLUSIONS: Delayed-type hypersensitivity reactions to iodinated contrast media are rare. We recommend that patients with delayed exanthematous reactions undergo patch or intradermal tests with different contrast media and their additives, and that readings be performed immediately and later at days 2 and 3.     

Diagnostic quality in hysterosalpingography. Comparison between iodixanol and iotrolan

PURPOSE: To compare the diagnostic quality and adverse events of the water-soluble, non-ionic, iso-osmolar, dimeric contrast media iodixanol and iotrolan in hysterosalpingography (HSG). MATERIAL AND METHODS: One hundred and twenty patients participated in a double-blind randomized parallel-group phase-III study. Questionnaires and patient interviews were used. Diagnostic quality was assessed using a visual analogue scale and the quality in specific regions was rated using a categorical scale. RESULTS: Overall diagnostic quality was equal for the two groups. There was no statistically significant difference between the two groups in diagnostic quality in the specific regions of interest. No differences between the contrast media were found with regard to adverse events. CONCLUSION: Both contrast media provided images of high diagnostic quality in HSG.     

Cerebral angiography with iohexol. A multicentre clinical trial

An open multicentre clinical trial with the new non-ionic contrast medium iohexol is reported. A total of 38 adult patients were included in the series. No serious side effects or complications occurred. The impression was that subjective reactions were less marked with iohexol than what is usually observed with conventional ionic contrast media.     

Head pain associated with sixth-nerve palsy: spontaneous dissection of the internal carotid artery

BACKGROUND: Iodixanol (Visipaque, Nycomed Imaging AS, Oslo, Norway) is a new non-ionic and isotonic X-ray contrast medium. OBJECTIVE: To assess its safety and efficacy for paediatric excretory urography. MATERIALS AND METHODS: A three-centre trial in which 72 patients were randomised into three parallel groups: iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iohexol 300 mgI/ml (Omnipaque, Nycomed Imaging, Oslo, Norway). Doses ranging from 1 to 3 ml/kg never exceeded 50 ml. Pulse rate and blood pressure were recorded before, during, and after the examination. Adverse events, including injection associated discomfort, were recorded during and up to 24 h after the examination. The diagnostic quality of the urograms was assessed on a four-level scale. RESULTS: No serious adverse event occurred in any of the three groups. One patient who was given iodixanol 270 mgI/ml, three who received iodixanol 320 mgI/ml, and one who received iohexol 300 mgI/ml experienced transient adverse events. More than 80 % of the urograms in all three groups were rated "good" or "excellent". CONCLUSION: Iodixanol, either 270 mgI/ml or 320 mgI/ml, is well tolerated and efficacious for excretory urography in children.     

Does the preoperative administration of ketorolac improve postoperative analgesia

AIM OF THE STUDY: 1) To verify the usefulness of ketorolac administration (30 mg i.v.) before a surgical operation in terms of postoperative analgesia improvement; 2) To evaluate the impact of preoperative ketorolac administration on perioperative renal function and on intraoperative water balance; 3) to evaluate the presence of adverse effect due to preoperative NSAID use. DESIGN: Prospective randomized trial. SETTING: University surgical department. PATIENTS AND METHODS: Forty adult patients undergoing major abdominal surgery, randomized in 2 groups: in group 1 ketorolac (30 mg i.v.) was administered immediately after the induction and, for postoperative analgesia, ketorolac (30 mg i.v.) was administered beginning at the time of skin closure; in group 2 no ketorolac was administered before the operation and postoperative treatment was the same. Buprenorphine (0.3 mg i.m.) was administered in case of unsatisfactory analgesia. Fluids infused and diuresis were measured intraoperatively. One, 6 and 24 hours after the end of operation pain was evaluated using pain intensity score and VAS. The day after the operation serum creatinine and urea were measured. RESULTS: No statistically significant differences were found between groups regarding fluids infused, intraoperative diuresis, postoperative pain, adverse effects and number of bleeding episodes. More than 50% of patients, in either groups, required opioids administration. CONCLUSIONS: Ketorolac (30 mg i.v.) administration before a major abdominal operation does not improve postoperative analgesia nor determines significant alterations in renal function or increase in the frequency of abnormal bleedings. Opiate administration is necessary in more than 50% of the patients to achieve adequate analgesia.     

Aspiration after administration of oral contrast material in children undergoing abdominal CT for trauma

OBJECTIVE: The practice of routinely administering oral contrast material to children undergoing abdominal CT for blunt trauma is controversial, primarily because of the increased risk of aspiration. The purpose of this study was to determine how often aspiration occurs in this population of children. MATERIALS AND METHODS: We retrospectively studied 50 children who underwent abdominal CT scans after blunt trauma. All children received diluted 3% water-soluble oral contrast material. The medical record of each child was reviewed for evidence of aspiration pneumonia as many as 48 hr after the CT. In each patient, sections of the CT scan through the lung bases were examined for opacities. When lung opacities were identified, they were classified as atelectasis, confusion, laceration, or nonspecific. We made attenuation measurements of lung opacities larger than 1 cm, and each measurement was compared with the attenuation measurement of contrast material in that patient's stomach. Student's two-tailed t test was used to compare the two measurements. RESULTS: Four patients were febrile after the CT scan, but in none was aspiration pneumonia suspected to be the cause. The remaining 46 patients did not have any clinical evidence of aspiration. Twelve of the 50 patients had pulmonary opacities revealed by CT that were sufficiently large that attenuation measurements could be obtained. The opacity in one of these patients was classified as nonspecific, and the attenuation was as high as that of contrast material in the stomach. CONCLUSION: No clinically symptomatic episodes of aspiration pneumonia were found in 50 pediatric patients with blunt trauma who were given oral contrast material for abdominal CT. Although one of the children had CT findings that suggested clinically silent aspiration of oral contrast material, no evidence was found that administration of oral contrast material was harmful.     

Sustained transmission of mumps in a highly vaccinated population: assessment of primary vaccine failure and waning vaccine-induced immunity

Electrolyte addition to nonionic contrast media has been suggested to further reduce the incidence of ventricular fibrillation during coronary arteriography. The present study was designed to investigate the effects of adding 30 mM NaCl, 0.9 mM KCl, 0.15 mM CaCl2 and 0.1 mM MgCl2 to iohexol on cardiac electrophysiology and hemodynamics (iohexol+electrolytes = IPE). Contrast media were injected into the left main coronary artery in 9 open-chest, anesthetized dogs before and after induction of acute ischemic heart failure. IPE increased left ventricular inotropy (LV dP/dtmax) with no initial decrease, even during heart failure. During heart failure IPE induced the same hemodynamic effects as iohexol without electrolyte addition. IPE slightly lengthened epicardial monophasic action potential duration before heart failure. We conclude that IPE appears to be well tolerated hemodynamically. The electrophysiologic differences between IPE and iohexol are small when the injection time is not longer than 5 s.     

Quantitative assessment of platelet function and clot structure in patients with severe coronary artery disease

RATIONALE AND OBJECTIVES: Although systemic absorption of enterically administered iohexol and its excretion in urine has been previously documented in rats with ischemic bowel, a practical and sensitive method of detecting urinary iohexol has not been available. We proposed to detect the presence of iohexol in the urine of rats with normal and ischemic bowel by use of a computed tomography (CT) number increase in the bladder with the use of CT. METHODS: Anesthetized rats (250 g) underwent either sham laparotomy (n = 6), ligation of two vascular arcades to the proximal jejunum (n = 5), ligation of six vascular arcades to the proximal jejunum (n = 6), or ligation of the superior mesenteric artery (n = 6). Rats were hydrated with saline (3.2 ml/hr intravenously). Each received a 3-ml enteric bolus of isotonic iohexol. Serial CT scans and plain film radiographs of the bladder were performed at 2, 4, and 6 hr to detect systemic absorption of contrast from the gut. Urine iohexol concentrations were measured by capillary electrophoresis. CT number and iohexol concentration were compared with evidence from plain film radiographs of bladder opacification. Intestinal ischemia was graded histologically. RESULTS: Histologic evidence of ischemia was present in all six-arcade and five of six superior mesenteric artery (SMA)-ligated animals. No animals in the control or two-arcade group showed evidence of bowel ischemia. Statistically significant increases (P < 0.05) in bladder density were demonstrated in the six-arcade and SMA-ligated groups. No statistical difference was noted between the two-arcade ligation and control groups. CONCLUSIONS: Experimental intestinal ischemia was reliably detected by bladder opacification after administration of enteric contrast. CT detection of systemic absorption of enteric iohexol was more sensitive than plain film radiographs and may be useful in the diagnosis of intestinal ischemia, although it may not be specific for ischemia.     

Hypotensive reactions to white cell-reduced plasma in a patient undergoing angiotensin-converting enzyme inhibitor therapy

BACKGROUND: Hypotensive reactions to platelet transfusions performed with white cell (WBC)-reduction filters with negatively charged surfaces have been reported recently in patients taking angiotensin-converting enzyme (ACE) inhibitors. Experimental studies have shown that the filter material can activate bradykinin, which may cause symptoms in patients with reduced bradykinin catabolism. Symptomatic adverse reactions after the administration of fresh-frozen plasma (FFP) through a WBC-reduction filter have not been reported in a patient on ACE Inhibitor medication. CASE REPORT: A 58-year-old man with congenital coagulation factor V deficiency and hypertension treated with an ACE inhibitor was admitted for rehabilitation after orthopedic surgery. On 3 consecutive days, he received FFP through a WBC-reduction filter; within minutes of the beginning of each infusion, he experienced a drop in blood pressure, facial erythema, abdominal pain, and anxiety. When the infusions were stopped, symptoms quickly abated without treatment. Multiple prior transfusions of unfiltered FFP and FFP filtered through a WBC-reduction filter made by a different manufacturer, as well as subsequent transfusions of unfiltered FFP, had not produced such reactions. CONCLUSION: Facial flushing, hypotension, and abdominal pain after FFP administration in a patient on ACE inhibitor medication appeared to be associated with a specific type of WBC-reduction filter. This association and other reported studies suggest that special caution is warranted when patients who are treated with ACE inhibitors receive blood components administered through WBC-reduction filters capable of generating bradykinin.     

Ketorolac vs meperidine for the management of pain in the emergency department

OBJECTIVE: To compare the pain relief, sedation, and common side effect profiles of ketorolac tromethamine and meperidine for the management of acute pain in the emergency department (ED). METHODS: A prospective, double-blind, randomized clinical trial was conducted over a 12-month period using consecutive adult patients presenting to a university teaching hospital ED (annual census: 32,000), who required IM analgesia for acute pain. Adult patients with acute pain of various etiologies were randomly assigned to receive a single fixed IM dose of ketorolac (60 mg) or meperidine (100 mg). RESULTS: Ninety-three patients were enrolled in the study; 46 were randomized to meperidine and 47 to ketorolac. Using a visual analog scale, there was no difference in pain relief between the ketorolac and meperidine groups even after adjusting for baseline pain level. Ketorolac caused significantly (p < 0.005) less sedation than did meperidine at one hour. Rescue analgesia was required for seven of the 46 (15.2%) patients receiving meperidine and five of the 47 (10.6%) patients receiving ketorolac (p = NS). Seventeen of 45 (38%) patients receiving meperidine experienced side effects compared with eight of the 47 (17%) patients receiving ketorolac (p = 0.0452). CONCLUSIONS: When used to treat patients who had acute pain states, 60 mg of IM ketorolac produced analgesia similar to that produced by 100 mg of IM meperidine; however, the ketorolac produced fewer subjective side effects and less sedation than did the meperidine.     

Carbohydrate-deficient transferrin values in neonatal and umbilical cord blood

We set out to determine the extent to which two groups of patients reported having been informed about the adverse effects of NSAIDs. These consisted of 50 patients who had suffered an acute gastrointestinal bleed while taking a NSAID, and 100 age, sex and drug matched controls who had not. Eight (16%) of the index patients, and 41 (41%) of the control patients remembered having been informed of potential adverse effects, an odds ratio of 3.65 (95% CI 1.55-8.58, P < 0.002). Two (4%) of the index patients recalled having been advised what to do should adverse symptoms develop, whereas 21 (21%) of the control patients did so, an odds ratio of 6.38 (95% CI 1.4-28.4, P < 0.01). Eighteen (36%) of patients who bled had experienced gastrointestinal pain prior to the bleed, but of these only two (11%) admitted reduced compliance with NSAID therapy. In contrast, 10 (67%) of the 15 control patients who had suffered epigastric discomfort admitted reduced compliance, an odds ratio of 16.0 (95% CI 2.6-98.8, P < 0.001). Our results suggest that patients who report not having been informed of adverse effects of NSAIDs are less likely to reduce intake in response to epigastric pain than patients who report having received such information. If the patients who bled had reduced their intake of NSAIDs to the same extent as apparently better informed control patients in response to epigastric pain, it is possible that some episodes of acute gastrointestinal bleeding would have been avoided.     

Myelography in the dog with non-ionic contrast media at different iodine concentrations

Image quality and side effects were evaluated retrospectively in a series of 183 myelographic studies performed with two non-ionic contrast media (iohexol and iopamidol) at different concentrations. Side effects during and following the procedure were recorded. Image quality was assessed using an arbitrary scoring system and statistical analysis was performed with the cross-tabulation test (4 x 2 table) by comparing two groups receiving contrast medium at higher and lower concentrations. No significant differences in side effects were observed between the two groups but the ratings for image quality were significantly higher in the group receiving contrast medium at the higher concentration than in the group receiving the lower concentration. The results suggest that a high concentration of non-ionic contrast media can safely be used in dogs and may improve image quality.     

Adverse events and cost savings three years after implementation of guidelines for outpatient contrast-agent use

The ability of guidelines limiting the use of low-osmolality contrast media (LOCM) to save money without jeopardizing patient care was studies. In February 1993 an academic medical center implemented guidelines to reduce the use of LOCM for outpatient computed tomography and excretory urography; the guidelines limited LOCM to patients at high risk of adverse reactions to contrast agents. Data on contrast media received and frequency of adverse events were compiled from billing sheets and incident reports for March 1993 through February 1996. The number of patients receiving LOCM over the three years was 1325, and the number receiving high-osmolality contrast media (HOCM) was 4435. Of the HOCM recipients, 165 (3.7%) had adverse reactions; 0.4% of these reactions were major, 3.1% were minor, and 0.2% were extravasations. Among LOCM-treated patients, 35 (2.7%) had adverse reactions; 0.5% were major, 1.7% were minor, and 0.5% were extravasations. The only significant difference in adverse effects between the groups was in the frequency of minor reactions. The costs of HOCM and LOCM over the three years were $54,660 and $152,523, respectively. Had 90% of the 5760 patients received LOCM, the total cost of contrast agents would have been $603,723; thus, the estimated drug cost saving was $396,540, or $132,180 annually. With costs of treating adverse events factored in, the net annual cost saving was $132,093. Guidelines limiting the use of LOCM to high-risk patients saved an academic medical center an estimated $132,093 annually in drug costs for specific outpatient imaging procedures, without adversely affecting patient care.     

Comparison of carbon dioxide and normal saline for uterine distension in outpatient hysteroscopy

OBJECTIVE: To evaluate patient acceptance and the clinical feasibility of carbon dioxide compared with normal saline for uterine distension in outpatient hysteroscopy. DESIGN: Prospective, randomized clinical trial. SETTING: Outpatient hysteroscopy clinic in a university hospital. PATIENTS: One hundred fifty-seven patients undergoing outpatient hysteroscopy. INTERVENTIONS: Outpatient hysteroscopy was performed with carbon dioxide or normal saline with endometrial biopsy when indicated. MAIN OUTCOME MEASURES: Need for local anesthesia, cervical dilatation, view of uterine cavity, need to change from carbon dioxide to normal saline distension, procedure time, patient discomfort (lower abdominal pain, shoulder tip pain, nausea) and complications. RESULTS: Carbon dioxide was used for uterine distension in 79 women and normal saline was used in 78. Cervical dilatation was required more often with carbon dioxide hysteroscopy, although there was no increased requirement for local anesthesia. Hysteroscopic vision was similar between the two media, but eight carbon dioxide cases had to be converted to liquid distension. Procedure times were significantly longer for carbon dioxide hysteroscopy as was the occurrence of bubbles during the procedure. Lower abdominal pain and shoulder tip pain were significantly worse with carbon dioxide distension. Although the incidence of nausea and vomiting was higher with the use of carbon dioxide, the differences did not achieve statistical significance. CONCLUSION: The use of normal saline for uterine distension had no adverse affects on the hysteroscopic view. It provided a shorter operating time and was well accepted by patients. Because of its easy availability and low cost, normal saline is an excellent alternative to carbon dioxide in women undergoing outpatient hysteroscopy.     

Abdominal epilepsy in an adolescent with bilateral perisylvian polymicrogyria

PURPOSE: We report a patient with recurrent episodes of severe periumbilical pain accompanied by headache, pallor, dizziness, and visual hallucinations who was subsequently diagnosed as having abdominal epilepsy and a bilateral sylvian cortical malformation. METHODS AND RESULTS: During an EEG examination, the patient had a simple partial seizure, manifested as intense abdominal pain. The ictal EEG showed a focal electrographic seizure arising from the left frontotemporal region. Computed tomography scan was normal; however, magnetic resonance imaging (MRI) revealed asymmetric lesions involving both sylvian fissures compatible with polymicrogyria. Onset of treatment with sodium valproate was followed by a significant reduction of seizures. CONCLUSIONS: Abdominal epilepsy should be suspected in adolescents or adults with paroxysmal episodes of abdominal pain associated with migraine-like symptoms. EEG and MRI investigations are indicated. A developmental brain disorder should be considered as a possible etiology.     

The allergic theory of radiocontrast agent toxicity: demonstration of antibody activity in sera of patients suffering major radiocontrast agent reactions

An allergic, immunologic mechanism for certain adverse reactions to radiocontrast agents has been postulated on the basis of clinical and theoretical considerations. One obstacle to the acceptance of this allergic theory has been the inability to demonstrate significant antibodies with specificity for these agents. In our studies, rabbits were immunized with 4 analogues of radiocontrast agents which induced IgG or IgE antibodies specific for the contrast media analogues. Then, to determine if antibodies to contrast agents were present in man a prospective, one-year surveillance of radiocontrast agent reactions was undertaken. Sera from 27 patients suffering severe reactions and 37 control subjects were analyzed by radioimmunoassay for antibodies reactive with radiocontrast media. Binding of radiolabeled contrast media was significantly elevated (p less than 0.01) by the serum globulin fraction of the patients suffering severe reactions. Demonstration of this antibody activity, although not proof of cause and effect between the presence of antibody activity and clinical symptoms, nonetheless adds support to the hypothesis that some adverse reactions to radiocontrast agents are due to antibodies.     

Hepatic imaging with iodinated nanoparticles: a comparison with iohexol in rabbits

RATIONALE AND OBJECTIVES: We evaluated the efficacy of a particulate computed tomography (CT) contrast agent in an animal model of focal liver disease. METHODS: Ethyl ester of diatrizoic acid (EEDA) is an iodinated (89 mg I/ml) nanoparticulate (200 nm) contrast agent intended for intravenous use that is currently undergoing preclinical testing in our laboratory. Focal liver abscesses were created in 11 New Zealand White rabbits. Iohexol and EEDA were administered to each animal on different days. CT scanning was performed at intervals following contrast agent administration. Liver and abscess enhancement were measured and compared. Dynamic imaging experiments in normal animals were also performed using both agents. RESULTS: EEDA resulted in significantly greater enhancement of the liver and liver-to-abscess contrast than did iohexol at all time points beyond 5 min at approximately 25% of the total iodine load. During dynamic imaging, liver and aortic enhancement were greater with EEDA than with iohexol, except during a 20- to 40-sec period immediately following contrast agent administration. CONCLUSION: EEDA is superior to iohexol for imaging liver abscesses. Our results suggest that liver-directed agents such as EEDA may prove to be more efficacious than currently available extracellular agents designed for liver CT scanning.