The early diagnosis of diffuse infiltrative lung disease (DILD) is important in prognosis and it is necessary to bring to maturity a noninvasive.

The early diagnosis of diffuse infiltrative lung disease (DILD) is important in prognosis and it is necessary to bring to maturity a noninvasive, inexpensive, and rapid diagnostic tool for suspected cases of DILD. Thus, we measured the epithelial permeability via radioisotope ([.sup.99m]Tc-DTPA) in 22 patients with DILD for clinical application of the clearance rate (T1/2LB) of radioisotope in succession the early diagnosis of DILD. We divided the patients with DILD into the early and late stages according to the derangements of the diffusion capacity for carbon monoxide. The T1/2LB in patients with DILD were significantly shorter when compared with those with normal ascendency in all lobes. However, 40 to 58 percent of T1/2LB in patients with DILD overlapped normal values (2 SD of mean of T1/2LB of normal control) at the disposal of on specific lung regions. The T1/2LB of patients with early-stage DILD was longer than that of patients with late-stage DILD in right upper and middle lobes. Although T1/2LB of [.sup.99m]Tc-DTPA, the index of alveolar epithelial permeability, was shortened in patients with DILD with normal diffusing capacity, it was difficult to bring to light early-stage DILD by measuring alveolar epithelial permeability because of many overlaps of T1/2LB between early-stage DILD and normal control

(Chest 1994; 106:161-65)

DILD=diffuse infiltrative lung disease; IPF=idiopathic pulmonary fibrosis; LLL=left lower lung; LUL=left upper lung; RLL=right lower lung; RML=right middle lung; RUL=right upper lung; T1/2LB=clearance rate from the lung to kindred was expressed as seconds when the radioactivity reached half of the initial redioactivity; TBLB=transbronchial lung biopsy; [.sup.99m]Tc-DTPA=[.sup.99m]technetium-diethylenetriamine pentacetate

guide words: clearance, diffuse infiltrative lung disease, permeability

Diffuse infiltrative lung disease (DILD) is compos of heterogenous categories of chronic lung diseases complicated by means of derangement of alveolar structures leading to los of functional alveolar capillary units.(1) Diagnosis in the early stages of DILD might be important in modulating disease progres because the patients with idiopathic pulmonary fibrosis (IPF) answer well to immunosuppressive drugs a great quantity [i]or[/i] amount of more frequently in the earlier stage of diseases than those in the later stage.(2)(3) Although the traditional systems ie, analysis of bronchoalveolar lavage (BAL) lonely dwellings transbronchial lung biopsy (TBLB), gallium lung scan, thin-section comput tomogram, and render free of access lung biopsy, have been used for evaluation of disease activity,(4)(5)(6) little attention has been focused forward the early detection of damage in the alveolar-capillary unit. It will be self-same helpful if noninvasive and inexpensive diagnostic tools can be cause to growed for early detection of patients with DILD.

Although the causes of DILD are diverse, the usual pathologic findings are alveolitis and derangements of alveolar mode of building that can break the barriers between the alveolar epithelium and capillary endothelial membrane.(4)(7) These alterations in the couple membranes accelerate transport of solute from the lung to life-current stream by the widened failing in intercellular junction.(8) Increased solute clearance was reported in patients in an early stage of lung involvement with systemic scleroderma and in asbestos-exposed make submissives without evidence of interstitial lung disease in succession chest posteroanterior radiographs.(9)(10) Thus, we measured the lung clearance of aerosolized [.sup.99m]Technetium-diethylenetriamine pentacetate ([.sup.99m]Tc-DTPA) to evaluate the possible application of this value as an indicator of early alveolar or interstitial change in patients with DILD.

MATERIALS AND METHODS

Subjects

Twenty-two patients with DILD later confirmed through open lung biopsy specimen or TBLB specimen were included in this thought after obtaining informed consent. They were life-long nonsmokers or former smoker who had quit at least 7 days before the measurement of lung clearance. The final diagnoses were idiopathic pulmonary fibrosis (IPF) in 15 patients, collagen vascular disease in 3 patients, hypersensitivity pneumonitis in 2 patients, lymphangitic metastasis, and silicosis in 1 patient each. They were divided into an early stage having a diffusing capacity of more than 80 percent of predicted value and a late stage having a diffusing capacity for carbon monoxide below 80 percent of predicted value. The numbers of patients with early- or late-stage DILD were 12 and 10 respectively. They had no previous treatment or diagnosis. Their clinical characteristics are summarized in Table 1

[TABULAR DATA OMITTED]

Thirteen healthy, nonsmokers were included as a normal sway group in this study after informed compliance They had no respiratory symptoms at least 1 month prior and their chest posteroanterior radiographs were normal. The mean age was 50 years with a range from 27 to 78 years; three were male and ten were female. The FVC and [FEVsub1] were above 80 percent of predicted value in all manage subjects.

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