IMAGING CHARACTERISTICS OF INTRAOCULAR FOREIGN BODIES A Comparative Study of Plain Film X-Ray, Computed Tomography, Ultrasound, and Magnetic Resonance Imaging

Purpose: To determine the imaging features of common intraocular foreign bodies (IOFBs) and the ability to differentiate types of IOFBs. Methods: Four-mm IOFBs were inserted via through pars plana approach into cadaveric lamb eyes. Six metallic (aluminum, brass, copper, silver, steel, and lead) and seven nonmetallic (plastic [CF6 spectacle plastic and polyvinyl chloride pipe], glass [bottle glass and windshield glass], wood [dry and wet poplar], and stone [slate]) IOFBs were imaged using plain film x-ray, computed tomography scan, ultrasound, and magnetic resonance imaging (T1, T2, and gradient echo sequences). Results: Plain film x-ray had limited ability to differentiate most IOFBs. Computed tomography findings can be divided into low attenuation objects (wood), moderate attenuation (CF6 spectacle plastic), high attenuation without surrounding artifact (polyvinyl chloride, slate, bottle glass, windshield glass, and aluminum), high attenuation with shadow artifact and minimal edge streak artifact (steel, brass, copper), and high attenuation with significant shadow artifact and prominent streak artifact (silver and lead). Density (in Hounsfield units) aided in differentiating the types of IOFBs. Gradient echo sequences on magnetic resonance imaging also held utility. Ultrasound images had considerable overlap in appearances. Conclusion: Imaging techniques can significantly aid in determining the IOFBs type, with computed tomography serving as the best initial modality. X-ray holds limited utility while ultrasound and magnetic resonance imaging are best reserved as adjunctive tests

Clinical scoring system may improve yield of head CT of non-trauma emergency department patients

The positive rate of head CT in non-trauma patients presenting to the emergency department (ED) is low. Currently, indications for imaging are based on the individual experience of the treating physician, which contributes to overutilization and variability in imaging utilization. The goals of this study are to ascertain the predictors of positive head CT in non-trauma patients and demonstrate feasibility of a clinical scoring algorithm to improve yield. We retrospectively reviewed 500 consecutive ED non-trauma patients evaluated with non-contrast head CT after presenting with headache, altered mentation, syncope, dizziness, or focal neurologic deficit. Medical records were assessed for clinical risk factors: focal neurologic deficit, altered mental status, nausea/vomiting, known malignancy, coagulopathy, and age. Data was analyzed using logistic regression and receiver operator characteristic (ROC) curves and three derived algorithms. Positive CTs were found in 51 of 500 patients (10.2 %). Only two clinical factors were significant: focal neurologic deficit (adjusted odds ratio (OR) 20.7; 95 % confidence interval (CI) 9.4-45.7) and age >55 (adjusted OR 3.08; CI 1.44-6.56). Area under the ROC curve for all three algorithms was 0.73-0.83. In proposed algorithm C, only patients with focal neurologic deficit (major risk factor) or ≥2 of the five minor risk factors (altered mental status, nausea/vomiting, known malignancy, coagulopathy, and age) would undergo CT imaging. This may reduce utilization by 34 % with only a small decrease in sensitivity (98 %). Our simple scoring algorithm utilizing multiple clinical risk factors could help to predict the non-trauma patients who will benefit from CT imaging, resulting in reduced radiation exposure without sacrificing sensitivity

Clinical scoring system may improve yield of head CT of non-trauma emergency department patients

PURPOSE: The positive rate of head CT in non-trauma patients presenting to the Emergency Department (ED) is low. Currently, indications for imaging are based on the individual experience of the treating physician, which contributes to overutilization and variability in imaging utilization. The goals of this study are to ascertain the predictors of positive head CT in non-trauma patients and demonstrate feasibility of a clinical scoring algorithm to improve yield. METHODS: We retrospectively reviewed 500 consecutive ED non-trauma patients evaluated with non-contrast head CT after presenting with headache, altered mentation, syncope, dizziness, or focal neurologic deficit. Medical records were assessed for clinical risk factors: focal neurologic deficit, altered mental status, nausea/vomiting, known malignancy, coagulopathy, and age. Data was analyzed using logistic regression and receiver operator characteristic (ROC) curves and 3 derived algorithms. RESULTS: Positive CTs were found in 51 of 500 patients (10.2%). Only two clinical factors were significant. Focal neurologic deficit (adjusted OR 20.7; 95% CI 9.4–45.7) and age >55 (adjusted OR 3.08; CI 1.44–6.56). Area under the ROC curve for all 3 algorithms were of 0.73–0.83. In proposed Algorithm C, only patients with focal neurologic deficit (major risk factor) or ≥2 of the five minor risk factors (altered mental status, nausea/vomiting, known malignancy, coagulopathy, and age) would undergo CT imaging. This may reduce utilization by 34% with only a small decrease in sensitivity (98%). CONCLUSION: Our simple scoring algorithm utilizing multiple clinical risk factors could help to predict the non-trauma patients who will benefit from CT imaging, resulting in reduced radiation exposure without sacrificing sensitivity