Normal values for quantitative parameters for evaluation of mucociliary clearance in lungs.

Abstract

Twenty-eight normal male subjects (13 nonsmokers and 15 smokers, 25 to 76 years of age) inhaled ultrasonically generated 99mTc-tagged human serum albumin aerosol (mass median diameter : 1.93,um with geometric standard deviation of 1.52) and radioactivity from the thorax was measured continuously from anteriorly in 10 sec frame mode for 90 to 120 min to evaluate mucociliary clearance function in the lungs. Normal values for lung retention ratio (LRR), airway deposition ratio (ADR), airway retention ratio (ARR), airway clearance efficiency (ACE), alveolar deposition ratio (ALDR), and disappearance rate of radioactivity from the ciliated airways (DR) were presented. ALDR was significantly larger in nonsmokers than in smokers. LRR and ARR were significantly smaller and ACE, significantly larger in smokers at any time intervals than in nonsmokers, while ADR and DR were larger in smokers only in the initial 30 min following radioaerosol inhalation was completed. Thereafter there was little difference in ADR and DR between normal smokers and nonsmokers.airway clearance efficiency ; airway deposition ratio ; airway retention ratio ; alveolar deposition ratio ; lung retention ratio Radioaerosol inhalation lung cine-scintigraphy has made it possible to visually evaluate how mucociliary clearance mechanisms are functioning in the lungs especially on the trachea and the proximal main bronchi (Isawa et al. 1981). While the mucous flow is invariably cephalad in direction in normal subjects (Isawa et al. 1981(Isawa et al. ,1984a, frequent stopping and starting of mucous globs, reversal of mucous flow, straying of the mucous globs to different regions of the lungs or even to the opposite lung, and/or zigzag motions are observed in patients with obstructive airways disease (Isawa et al. 1981(Isawa et al. , 1984. In addition to mucus

Ventilation scintigraphy with lipophilic cationic compounds

“…About 75% of inhaled activity was deposited in lungs with radiolabeled MIBI and tetrofosmin compared with 65% with 99m Tc-DTPA. This compares well with the literature reporting similar deposition fraction with technegas and particulate radioaerosols, respectively [9][10][11]. Considering that our series of patients had generally a poor respiratory capacity, we are almost certain that the quality of ventilation scans with lipophilic cation radioaerosols will at least match those obtained with technegas.…”

“…This translates into the need to increase the output of nebulized radioaerosols with low activity median aerodynamic diameter (AMAD) favoring lung deposition. Using specialized nebulizer equipment, lung deposition up to 40% has been achieved with particulate aerosols [9], whereas that with nanoparticles of technegas is 85% [3,10,11]. One of the approaches we explored was the use of radiopharmaceuticals other than those already in clinical use as radioaerosols.…”

Airway Retention of Materials of Different Solubility following Local Intrabronchial Deposition in Dogs

“…Only a few attempted to isolate the bronchial clearance from whole lung clearance either by targeting deposition of the HSA to the central airways 28,29 or by correcting for alveolar deposition. 27 Bennett and Ilowite 28 and Ilowite et al 29 measured a mucociliary clearance rate of 0.7% per minute for HSA deposited centrally in healthy subjects. They showed about 20-30% overall lung clearance over a 60-min period with most of this presumed to be due to mucociliary clearance.…”

“…They showed about 20-30% overall lung clearance over a 60-min period with most of this presumed to be due to mucociliary clearance. After correcting for alveolar deposition, Isawa et al 27 measured about 40% clearance of material deposited in airways over a 90-min period. Both of these are less than the nearly 70% clearance that we measured for HSA in the DS ROI over a 60-min period and undoubtedly are influenced by the fact that in these previous studies HSA was deposited throughout the bronchial tree including small airways where the mucus transport rates are believed to be much slower than that in the relatively large airway in which we deposited the HSA in the current study.…”