Radiologic and Histopathologic Evaluation of Various Contrast Media for Bronchography

PURPOSE: To determine which contrast media are both efficient and safe for the imaging of airways. MATERIALS AND METHODS: We evaluated five contrast media (barium, gastrografin, iotrolan, ioxaglate, iopentol) in terms of image quality and their effects on the lungs of 25 white rabbits. For bronchography 0.5ml of contrast media was used. In each contrast group, HRCT scans were obtained immediately (n=5), 12 hours (n=4), 1 day (n=3), 2 days (n=2), and 1 week (n=1) after bronchography. Histopathologic specimens were obtained immediately, 12 hours, 1 day, 2 days, and 1 week later. Bronchograms were evaluated for image quality by three radiologists working independently, and were scored as 1(poor), 2(moderate), or 3(good) in terms of contrast quality and bronchial coating. HRCT was evaluated by two radiologists who reached a concensus; they determined the presence of contrast media, and then the pattern and extent of pulmonary opacity, and any related changes. Histopatholgic specimens were evaluated by two pathologists who sought consensus as to the extent of inflammation, pulmonary edema, and hemorrhage, and any changes in these aspects. RESULTS: Bronchography indicated that the sum of scores for contrast quality was 45 for barium, 33 for gastrografin, 28 for iotrolan, 30 for ioxaglate, and 28 for iopentol, while for each of these media, the sum of scores for bronchial coating was 39, 19, 25, 23, and 21, respectively. Barium showed the best image quality. In all rabbits, HRCT demonstrated the variable extent of groundglass attenuation and/or consolidation. Lesions were most extensive at 1-2 days and then regressed at 1 week; these HRCT findings correlated well with histologic findings. In histologic studies of all five contrast media groups, variable severe inflammatory reactions were observed, with or without necrosis, congestion, edema, and hemorrhage. It was noted that ioxaglate appeared to cause least tissue reaction. CONCLUSIONS: The imaging results of this experimental study indicate that for bronchography, barium is the best available contrast media, On the basis of the histologic and HRCT results, however, ioxaglate is the best.

Renal Excretion of Gastrografin after Oral Administration: Clinical Significance in Gastric Resection Patients

PURPOSE: To evaluate the clinical significance of renal excretion of oral Gastrografin in gastric resectionpatients. MATERIAL AND METHOD: Seven days affter gastric resection, eight normal volunteers and 30 patientsunderwent abdominal and CT scanning before and 1-1.5 his after oral administiration of Gastrografin. Theattenuation coefficients of the bladder were measured and the maximal attenuation difference between pre-andpost-gastrografin administration was calculated. RESULTS: In the control group, there was no abnormal renalexcretion of oral Gastrografin, though in 83 % of patients(25 of 30), this was demonstrated as focal increase inthe density (> or = 20 HU) of the bladder and/or collecting system, or ureteral opacification. Mean maximal densitydifference was 84.4+/-82.9HU in the patient group (n=24), with renal excretion of enteral Gastrografin and,3.5+/-4.4 HU in the control group (n=7), with statistical significance (Student's t-test, p<0.01). No patientshowed either radiological or clinical evidence of direct leakage from the suture site. Patients who underwenttotal gastrectomy showed a higher maximal density difference than those in whom gastrectomy was subtotal. CONCLUSION: Unless direct leakage is visvalized on fluoroscopy or spot films, renal excretion of oralGastrografin should not be regarded as a sign of anastomotic leakage. Situations other than leakage, e. g.increased mucosal permeability or absorption, or increased bowel transit time in postoperative duration, should beconsidered as possible causes.

Reduced Volume of Contrast Media: Effect on Vascular Opacification and Image Quality in Spiral CT of the Chest

PURPOSE: To evaluate the effect of reduced volume of contrast media on vascular opacification and image quality in spiral CT of the chest. MATERIALS AND METHODS: Sixty patients referred for chest CT were examined withspiral CT with 60ml(n=30) or 90ml(n=30) of 30% ionic contrast media(Rayvist 300 , Schering, Germany) alternately.Injection rate of each group was as follows : 2.0 ml/sec for 20 seconds followed by 1.0 ml/sec for 20 seconds in 60ml group and 2.0ml/sec for 45 seconds in 90ml group. Twenty-five seconds scanning delay was employed. For the objective comparison of vascular opacification, CT numbers were measured at superior vena cava, ascending and descending aorta, right and left pulmonary artery, left atrium, and inferior vena cava. For the subjective comparison three radiologists scored the grade of vascular opacification and image quality blindly and independently. All data were analyzed statistically. RESULTS: The mean values of measured CT numbers in 90ml group were higher than those in 60ml group(p <.05) at the same level. The overall mean score of vascular opacification in 90ml group was 2.86, and 2.31 in 60ml group(p <.0001). In the overall mean score of imagequality, there was no statistically significant difference between 90ml group(2.46) and 60ml group(2.40). CONCLUSION: Althought there is some degradation of vascular opacification in 60ml group, overall image quality is not degraded. Therefore, 60 ml of contrast media can be used in spiral CT of the chest without degradation ofoverall image quality except in spiral CT angiography.