Hyperpolarized helium 3 diffusion imaging of the lung.
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Asthma↗
Biomedical subjects
John R Mayo
Publications and source records attributed to John R Mayo.
Traumatic pneumothorax detection with thoracic US: correlation with chest radiography and CT--initial experience.
PURPOSE: To prospectively compare the accuracy of ultrasonography (US) with that of supine chest radiography in the detection of traumatic pneumothoraces, with computed tomography (CT) as the reference standard. MATERIALS AND METHODS: Thoracic US, supine chest radiography, and CT were performed to assess for pneumothorax in 27 patients who sustained blunt thoracic trauma. US and radiographic findings were compared with CT findings, the reference standard, for pneumothorax detection. For the purpose of this study, the sonographers were blinded to the radiographic and CT findings. RESULTS: Eleven of 27 patients had pneumothorax at CT. All 11 of these pneumothoraces were detected at US, and four were seen at supine chest radiography. In the one false-positive US case, the patient was shown to have substantial bullous emphysema at CT. Sensitivity and negative predictive value of US were 100% (11 of 11 and 15 of 15 patients, respectively), specificity was 94% (15 of 16 patients), and positive predictive value was 92% (11 of 12 patients). Chest radiography had 36% (four of 11 patients) sensitivity, 100% (16 of 16 patients) specificity, a 100% (four of four patients) positive predictive value, and a 70% (16 of 23 patients) negative predictive value. CONCLUSION: In this study, US was more sensitive than supine chest radiography and as sensitive as CT in the detection of traumatic pneumothoraces.
Adolescent↗
Traumatic aortic rupture: CT evidence of a dynamic process.
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Adult↗
Computer-simulated radiation dose reduction for abdominal multidetector CT of pediatric patients.
OBJECTIVE: Limiting CT radiation dose is especially critical when imaging children. The purpose of our study was to modify and test an accurate and safe tool for evaluating systematic dose reduction for abdominal multidetector CT (MDCT) in pediatric patients. MATERIALS AND METHODS: After validating the computer-simulation technique with a water phantom, we subjected the original digital scanning data for 26 contrast-enhanced abdominal MDCT scans (120 mA) obtained in infants and children (age range, 1 month-9 years; mean age, 3.1 years) to simulated tube current reduction (100, 80, 60, and 40 mA) by adding noise. this procedure created four additional examinations per child that were identical to the originals except for image noise. The 130 examinations were scored randomly, independently, and without prior knowledge of the children's diagnoses by three radiologists for depiction of high-visibility structures, such as adrenal glands and fat in the intrahepatic falciform ligament, and low-visibility structures, such as the extrahepatic hepatic artery, small intrahepatic vessels, and common bile duct. Aligned rank and Wilcoxon's signed rank tests were used for statistical analyses. RESULTS: Simulated tube current reduction significantly affected the detection of low-visibility structures (p < 0.001). Reduced detection in low-visibility structures was evident at a level less than or equal to 80 mA. No loss of detection in high-visibility structures was found at any tube current level (p > 0.5). CONCLUSION: The results of this computer simulation suggest that accurate abdominal MDCT can be performed in pediatric patients using substantially reduced radiation, depending on the indication for imaging. (In our case, the reduction was between 33% and 67%, depending on whether a high-visibility or low-visibility structure was being assessed.) This simulation technology can be applied to MDCT of other organ systems for systematic evaluation of radiation dose reduction.
Child↗
Spiral computed tomography for acute pulmonary embolism.
Imaging algorithms utilizing V/Q scanning, leg ultrasound and pulmonary angiography have substantial limitations, and may result in patients being treated on clinical grounds without a definitive diagnosis. Hence, the introduction of spiral CT angiography of the pulmonary arteries has been greeted with enthusiasm.
Acute Disease↗
CT-Directed microcoil localization of small peripheral lung nodules: a feasibility study in pigs.
Platinum microcoils were placed in porcine lungs to determine the feasibility for use as a lung nodule marker. Using computed tomography (CT) guidance, the microcoils were successfully deployed in 17 out of 19 attempts. Coil deployment depth ranged from 7 mm to 34 mm below the pleural surface. Moderate pneumothorax was detected after 3 of 19 microcoil insertions. No hemothorax or significant pulmonary hemorrhage was noted. Fluoroscopic guided thoracoscopic resection was successful in 10 of 12 attempts. Platinum microcoils can be safely and easily deployed into the lung parenchyma with minimal complication risk, and can be used to guide subsequent thoracoscopic wedge resection.
Animals↗