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Imaging Technology Offers Noninvasive Option for Monitoring Pulmonary Inflammation in Cystic Fibrosis Patients: Presented at ATS

By Peggy Peck

SEATTLE, WA -- May 26, 2003 -- Fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging may provide a noninvasive alternative to bronchoalveolar lavage (BAL) for evaluation of disease activity in patients with cystic fibrosis. This finding was reported here on May 19^th at the American Thoracic Society International Conference.

Data from a small feasibility study of seven patients with stable cystic fibrosis was presented by a team of pediatric critical care specialists and radiologists, including Daniel B. Rosenbluth, MD, associate professor of medicine and pediatrics, Washington University, in St. Louis, Missouri, United States.

Dr. Rosenbluth noted that the only current option for evaluation of pulmonary inflammation is BAL, a method that often does not achieve good sampling. An alternative approach is forced expiratory volume in 1 second (FEV₁), but this method lacks both sensitivity and specificity. By comparison, PET has demonstrated some utility for detecting and monitoring acute neutrophilic inflammation.

Seven stable cystic fibrosis patients aged 20 to 50 were recruited for the study. FDG (~10 mCi) was administered intravenously, followed by 60 minutes of dynamic image acquisition. The researchers used both compartmental modeling and Patlak graphical analysis to calculate the influx constant (K_i) -- a measure of net FDG uptake in tissue. To calculate the rate of FEV₁ decline, they plotted the calendar year's best FEV₁ readings versus patient age, and then applied linear regression to the last years of data.

The mean K_i for all lung regions was 11x10^-4 min^-1 (normal range: 3-8x10^-4 min^-1), and this correlated well with FEV₁ rate of decline and with mean neutrophil counts from BAL of 6.3x10³ cells/mm³.

This study was funded by the Cystic Fibrosis Foundation.


[Study title: Evaluating Pulmonary Inflammation with Fluorodeoxyglucose (FDG) and Positron Emission Tomography (PET) in Patients with Cystic Fibrosis (CF). Abstract 814]

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