99mTc-DTPA aerosol for same-day post-perfusion ventilation imaging: Results of a multicentre study

A multicentre study was performed in an attempt to evaluate a submicronic technetium-99m diethylene triamine penta-acetic acid aerosol generated by a newly developed delivery system, the aerosol production equipment (APE nebulizer), for same-day post-perfusion ventilation imaging in patients with clinically suspected pulmonary embolism. Quantitative comparison between the DTPA aerosol and krypton gas demonstrated a close correlation with respect to regional pulmonary distribution of activity and peripheral lung penetration (n=14,r=0.94,P<0.001 andr=0.75,P<0.0025, respectively). In 169 consecutive patients, DTPA aerosol images performed immediately following perfusion (inhalation scan I) were compared to those carried out on the next day (inhalation scan 11) with respect to image quality and assessment of perfusion-ventilation matches or mismatches. Agreement between inhalation scans I and II with respect to perfusion defects matched or mismatched to ventilation was found in 166/169 (98%) studies. The image quality of inhalation scan I was equal to that of scan II in 72%; inhalation scan I was superior in 11% of cases, while scan 11 was superior in 17%. This submicronic^99mTc-labelled DTPA aerosol is well suited for fast same-day post-perfusion ventilation imaging in patients with clinical suspicion of pulmonary embolism.     

67Ga scanning for assessment of disease activity and therapy decisions in pulmonary sarcoidosis in comparison to chest radiography, serum ACE and blood T-lymphocytes

In 60 patients with histologically proven sarcoidosis, 67Ga scanning was evaluated in terms of sensitivity and specificity for assessing disease activity and compared with chest radiography, serum ACE and blood T-lymphocytes. While 67Ga scans had the highest sensitivity (94%), the specificity was only 68%. The sensitivity of chest radiography was 80%, of serum ACE and blood T-lymphocytes 77% and 48%, respectively. While in patients with radiographical type I, 67Ga scanning, chest radiography and serum ACE had a sensitivity of 92%-100%, in patients with radiographical type II-III, only 67Ga scans had a sensitivity exceeding 90%. A 67Ga score correlated significantly with serum ACE levels (r = 0.59, P less than 0.001). After effective steroid treatment, 67Ga uptake and serum ACE activities decreased markedly. While in 25% of cases, chest radiography failed to provide reliable information, 67Ga scanning and serum ACE activities always proved useful in evaluating the course of the disease and the patient's response to steroid therapy. A negative 67Ga scan together with normal serum ACE levels seem to have a high predictive value for excluding active sarcoidosis.