Results of both protocols were compared by using the chi(2) test and Student t test. Effective dose was calculated on the basis of dose length product and volume CT dose index. Subjective vessel contrast was assessed by two radiologists in consensus. Pulmonary vessel enhancement and image noise were quantified signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Contrast medium was injected automatically with bolus tracking. Other scanning parameters were kept constant. Patients were randomly assigned to a 100-kVp (n = 30 17 men, 13 women mean age, 66 years +/- 17 range, 19-89 years) or 120-kVp (n = 30 15 men, 15 women mean age, 62 years +/- 15 range, 28-86 years) protocol. Sixty patients were referred for evaluation of suspected pulmonary embolism with CT angiography. The study had institutional review board approval written informed consent was obtained. To prospectively compare 16-section multidetector computed tomography (CT) at 100 and 120 kVp for image quality and radiation dose. These findings suggest that the additional risk of acute kidney injury accompanying administration of contrast medium (contrast-induced nephrotoxicity) may be overstated and that much of the creatinine elevation in these patients is attributable to background fluctuation, underlying disease, or treatment. The incidence of creatinine elevation in this group was statistically similar to that in the isoosmolar contrast medium group for all baseline creatinine values and all stages of chronic kidney disease. We identified a high incidence of acute kidney injury among control subjects undergoing unenhanced CT. The incidence of acute kidney injury in the low-osmolar contrast medium cohort paralleled that of the control cohort up to a creatinine level of 1.8 mg/dL, but increases above this level were associated with a higher incidence of acute kidney injury. No significant difference in incidence of presumed contrast-induced kidney injury was identified between the isoosmolar contrast medium and the control groups. In all groups, the incidence of acute kidney injury increased with increasing baseline creatinine concentration. Rates of acute kidney injury (defined as a 0.5 mg/dL increase in serum creatinine concentration or a 25% or greater decrease in estimated glomerular filtration rate within 3 days after CT) were compared among groups and stratified according to creatinine concentration and estimated glomerular filtration rate before the imaging examination. Creatinine concentration and estimated glomerular filtration rate were evaluated for 11,588 patients. The purpose of this study was a retrospective comparison of the incidence of acute kidney injury among patients undergoing CT with low-osmolar (iohexol) or isoosmolar (iodixanol) contrast medium with the incidence among patients undergoing CT without contrast administration. Almost no studies have been conducted to quantify the background fluctuation of kidney function of patients receiving iodinated contrast medium. The reported incidence of contrast-induced acute kidney injury varies widely. Clinical assessment combined with the ventilation/perfusion scan established the diagnosis or exclusion of pulmonary embolism only for a minority of patients-those with clear and concordant clinical and ventilation/perfusion scan findings. Follow-up and angiography together suggest pulmonary embolism occurred among 12% of patients with low-probability scans. Of 322 with intermediate-probability scans and definitive angiograms, 105 (33%) had pulmonary embolism. Of 116 patients with high-probability scans and definitive angiograms, 102 (88%) had pulmonary embolism, but only a minority with pulmonary embolism had high-probability scans (sensitivity, 41% specificity, 97%). Almost all patients with pulmonary embolism had abnormal scans of high, intermediate, or low probability, but so did most without pulmonary embolism (sensitivity, 98% specificity, 10%). Nine hundred thirty-one underwent scintigraphy and 755 underwent pulmonary angiography 251 (33%) of 755 demonstrated pulmonary embolism. To determine the sensitivities and specificities of ventilation/perfusion lung scans for acute pulmonary embolism, a random sample of 933 of 1493 patients was studied prospectively.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |