Quantitative gallium 67 lung scan to assess the inflammatory activity in the pneumoconioses

Association between gallium-67 uptake by lung foci and sputum smear status in patients with pulmonary tuberculosis

OBJECTIVES

Rapid determination of the inflammatory and sputum smear status in patients with pulmonary tuberculosis (PTB) is crucial for clinical decision making. The purpose of this study was to assess the relationship between gallium-67 (Ga-67) uptake by lung foci and sputum smear status in patients with PTB. We also attempted to predict the patients with acid-fast bacilli (AFB) smear-positive PTB by means of a semiquantitative measurement of Ga-67 uptake ratio using single-photon emission computed tomography images.

PATIENTS AND METHODS

Ninety-five patients with PTB were enrolled in this retrospective study. A volume-of-interest method was used to quantify Ga-67 uptake in single-photon emission computed tomography images. The Ga-67 uptake ratio was defined as the maximum voxel value of the pulmonary lesion divided by the maximum voxel value of normal lung tissue.

RESULTS

The Ga-67 uptake ratio was higher in patients with active PTB than in those with inactive PTB (3.11 ± 1.52 vs. 1.42 ± 0.14, P<0.01). In active PTB, the Ga-67 uptake ratio was higher in smear-positive patients than in smear-negative patients (3.41 ± 1.60 vs. 2.16 ± 0.61, P<0.01). In patients with AFB smear grades 1+, 2+, and 3+, the Ga-67 uptake ratios were 2.51 ± 0.81, 3.30 ± 1.57, and 4.23 ± 1.73, respectively. The correlation between Ga-67 uptake ratio and AFB smear grading was statistically significant (Spearman's ρ=0.60, P<0.01). In receiver operating characteristic curve analyses, the area under the curve for the Ga-67 uptake ratio was 0.95 ± 0.02 (P<0.01) for predicting active PTB and 0.87 ± 0.04 (P<0.01) for predicting smear-positive active PTB.

CONCLUSION

In patients with active PTB, more-intense Ga-67 uptake was associated with more AFB load in the sputum - that is a greater potential to transmit PTB. This finding might facilitate clinical decision making for immediate isolation and treatment to reduce transmission of PTB.

Whole-body gallium-67 scintigraphic findings in IgG4-related disease

PURPOSE

To clarify the features of gallium-67 (Ga-67) imaging typical of IgG4-related disease.

METHODS

We retrospectively investigated 14 patients diagnosed with IgG4-related disease who underwent Ga-67 scintigraphy in our hospital between January 2005 and May 2010. Of these, 13 patients who underwent gallium scintigraphy before steroid therapy were enrolled in this study. The patient population comprised 11 men and 2 women with age ranging from 47 to 76 years (mean age, 61.9 years).

RESULTS

Among the 13 patients, significant accumulation of Ga-67 was detected in the bilateral pulmonary hila in 10 patients (77%), pancreas in 10 (77%), salivary glands in 7 (54%), lacrimal glands in 7 (54%), periaortic lesions in 2 (15%), and lung parenchyma in 1 (8%) patient. High accumulation of Ga-67 in the salivary glands was observed in the parotid glands in 3 cases and in the submandibular glands in 6 cases, with the following pattern: normal parotid gland uptake and symmetrical submandibular gland uptake in 2 cases; symmetrical high accumulation in both parotid and submandibular glands in 1 case; symmetrical high accumulation in parotid glands and normal submandibular gland uptake in 1 case; symmetrical uptake by parotid glands and asymmetric uptake by submandibular glands in 1 case; normal parotid gland uptake and asymmetric submandibular gland uptake in 1 case; and asymmetric parotid gland uptake and symmetrical parotid gland uptake in 1 case.

CONCLUSION

Characteristic patterns of gallium uptake would be helpful for diagnosis, detection of involved lesions, and differential diagnosis in patients with IgG4-related disease to avoid unnecessary surgery.

Effects of cigarette smoking on diagnostic tests for work-related hypersensitivity pneumonitis: data from an outbreak of lung disease in metalworkers

BACKGROUND

It is widely believed that development of hypersensitivity pneumonitis (HP) is forestalled in cigarette smokers. We encountered the largest outbreak of HP in metalworkers yet reported [Hodgson et al. (2001): Am J Ind Med 39:616-628] and subsequently did a chart review of the 61 patients seen in connection with the outbreak [Dangman et al. (2002a): Am J Resp Crit Care Med 165(8):A528; Dangman et al. (2002b): Am J Ind Med 42:150-162], developing a diagnostic index for this disease.

METHODS

A re-examination of data from the chart review was carried out to explore possible effects of cigarette smoking on the clinical tests used to diagnose HP [Hodgson et al. (2001): Am J Ind Med 39:616-628].

RESULTS

Cigarette smokers with HP were less likely than non-smokers with HP to develop crackles in the lungs, elevated erythrocyte sedimentation rates (ESRs), and restrictive spirometry. Smoking habits had little effect on diffusion capacity and alveolar-arterial oxygen gradients in the patients with HP. Smokers were more likely to have abnormal gallium scans than non-smokers.

CONCLUSIONS

It appears that cigarette smoking can affect the physical examination findings, spirometry, and ESR changes associated with HP, making these tests less sensitive and specific, and potentially obscuring the diagnosis. Such changes may contribute to the apparent "protective" effect of smoking on the development of HP.

Chest radiography and high resolution computed tomography in the evaluation of workers exposed to silica dust: relation with functional findings

OBJECTIVES

To compare the usefulness of high resolution computed tomography (HRCT) with chest radiography (CR) in the diagnosis and assessment of severity of silicosis.

METHODS

27 workers exposed to silica underwent CR, HRCT, and pulmonary function tests. Two experienced readers independently evaluated CR by International Labour Office classification, and grouped the results into four categories. HRCT categories of nodule profusion and the extent of emphysema were graded on a four point scale; in 20 subjects the percentage distribution of lung densities were measured by HRCT.

RESULTS

Concordance between readers was higher for HRCT than for CR (K statistic = 0.49 and 0.29 respectively). There was poor concordance between CR and HRCT in the early stage of silicosis. No significant difference in pulmonary function tests was found among different CR categories, but forced expiratory volume in one second (FEV1), maximal expiratory flow at 50% and 75% of FVC (MEF50, MEF75), and diffusion capacity significantly decreased with increasing HRCT categories. Subjects with simple silicosis detected by HRCT had a lower FEV1 than subjects without silicosis, whereas subjects with conglomerated silicosis showed higher residual volume and functional residual capacity than subjects with simple silicosis. These relations were not affected by smoking or symptoms of chronic bronchitis. Different grades of emphysema detected by HRCT were significantly different in diffusion capacity. Only the HRCTs of the lowest and the highest categories of profusion of parenchymal opacities were significantly different in their distribution of density classes.

CONCLUSION

HRCT is more reproducible and accurate than CR, as suggested by the higher agreement between readers and the better correlation with pulmonary function tests, irrespective of smoking and chronic bronchitis; however, these data do not support the hypothesis that HRCT is more sensitive than CR in the early detection of silicosis.

HLA class I, II, and III polymorphism in Italian patients with sarcoidosis. The Pavia-Padova Sarcoidosis Study Group

We studied the HLA polymorphisms (class I, II, and III) in 107 Italian patients with biopsy specimen-proven sarcoidosis in order to investigate the immunogenetic background of this disease. The mean age of onset of the disease was 36.08 +/- 12.4 years. Four patients (3.73 percent) were in radiologic stage 0, 38 patients (35.51 percent) were in radiologic stage I, 40 patients (37.38 percent) were in stage II, and 25 (23.36 percent) were in stage III. Thirty-eight patients (35.51 percent) had one or more extrapulmonary localization(s) of the disease. Positive association between sarcoidosis and HLA-B8 (chi 2 = 6.07, p = 0.0127, RR = 1.91) was confirmed. Regarding the age of onset of the disease, HLA-B35 was more frequent (chi 2 = 7.34, p = 0.0056, pc < 0.05, RR = 4.62) in patients with early onset of symptoms and/or signs, before the mean age of 36 years. With reference to the radiologic stage of the disease, HLA class II marker DR3 was more frequent in patients with stage I (chi 2 = 7.22, p = 0.0061, pc < 0.05, RR = 7.08). No significant relationship was found between sarcoidosis and HLA class III markers. These results seem to confirm an association of sarcoidosis with HLA classic genes and can sustain the hypothesis of a genetic heterogeneity of this disease.

Computed tomography in the early detection of asbestosis

Computed tomography (CT; both conventional (CCT) and high resolution (HRCT)) scans of the thorax were evaluated to detect early asbestosis in 61 subjects exposed to asbestos dust in Québec for an average of 22(3) years and in five controls. The study was limited to consecutive cases with chest radiographs of the International Labour Organisation categories 0 or 1 determined independently. All subjects had a standard high kilovoltage posteroanterior and lateral chest radiograph, a set of 10-15 1 cm collimation CCT scans and a set of three to five 2 mm collimation HRCT scans in the upper, middle, and lower lung fields. Five experienced readers independently read each chest radiograph and sets of CT scans. On the basis of three to five readers agreeing for small opacities of the lung parenchyma, 12/46 (26%) negative chest radiographs were positive on CT scans, but 6/18 (33%) positive chest radiographs were negative on CT scan. On the basis of four to five readers agreeing on a chest radiograph, 36/66 (54%) subjects were normal (group A), 17/66 (26%) were indeterminate (group B), and 13/66 (20%) were abnormal (group C). By the combined readings of CCT and HRCT, 4/31 (13%) asbestos exposed subjects of group A were abnormal (p < 0.001), 6/17 (35%) of group B were abnormal, and in group C, 1/13 (8%) was normal, 2/13 were indeterminate, and 10/13 (77%) were abnormal. Separate readings of CCT and HRCT on distinct films in 14 subjects showed that all cases of asbestosis were abnormal on both CCT and HRCT. Inter-reader analyses by kappa statistics showed significantly better agreement for the readings of CT than the chest radiographs (p < 0.001), and for the reading of CCT than HRCT (p < 0.01). Thus CT scans of the thorax identifies significantly more irregular opacities consistent with the diagnosis of asbestosis than the chest radiograph (20 cases on CT scans v 13 on chest radiographs when four to five readers agreed, 13% of asbestos exposed subjects with normal chest radiographs or 21% of asbestos exposed subjects with normal or near normal chest radiographs. It decreased the number of indeterminate cases significantly from 17 on chest radiographs to 13 on CT scans. All cases of asbestosis detected only on CT scans were similarly seen on CCT and HRCT and did not have significant changes in lung function. The CT scans significantly reduced the inter-reader variability, despite the absence of ILO type reference films for these scans.

Severe hypersensitivity reaction to injectable Gallium 67 in a worker exposed to silica

Gallium 67 scintigraphy is employed in the evaluation of workers with possible pneumoconiosis. To our knowledge, however, a severe hypersensitivity reaction following the intravenous injection of Gallium 67 has not been described. We report the case of a worker chronically exposed to silica who developed an allergic cutaneous and severe articular reaction following the injection of Gallium 67 while being investigated for possible silicosis. Hilar adenopathy was noted on the chest roentgenogram and, retrospectively, circulating immune complexes were found in the patient's serum. The presence of a positive prick skin test to benzyl alcohol suggests that this preservative caused the hypersensitivity reaction.

Computer quantitation of gallium 67 lung uptake in crocidolite (blue asbestos) workers of Western Australia

Pulmonary inflammation has been evaluated in 43 crocidolite-exposed asbestos (ASB) workers and 12 control subjects, using a quantitative index of gallium uptake (GI). The GI was compared with chest roentgenographs (CXRs) graded by the ILO classification. The ASB workers included 15 with asbestosis (CXR greater than or equal to 1/0), 19 with a normal CXR (CXR 0/0), and 9 with equivocal CXR changes (CXR 0/1). In individuals with asbestosis the GI was 3.6 +/- 0.3 (mean +/- SEM), P less than 0.01 compared with exposed patients without asbestosis. In exposed patients with equivocal CXR changes (0/1) the GI was 3.1 +/- 0.3, and in exposed patients with a normal CXR (0/0) the GI was 2.4 +/- 0.2. The GI for subjects without lung disease was 1.2 +/- 0.2, P less than 0.01 compared with exposed patients without asbestosis. The scans were scored independently by two observers, and the correlation coefficient of the two sets of GI was 0.95. These data demonstrate that subjects with crocidolite-induced asbestosis and exposed patients with equivocal CXR changes or a normal CXR have significantly increased GI.

Elevated serum procollagen III aminopeptide levels in sarcoidosis

Procollagen III aminopeptide (P-III-P), a peptide released during the conversion of type III procollagen to type III collagen, is considered a potential marker of fibroblast activity in a variety of pulmonary and extrapulmonary diseases. The aim of the present article was to investigate the levels of P-III-P in serum samples (sP-III-P) from a large number of sarcoid patients, in particular looking at its relationship with other markers of disease activity and its presumed role as a marker of pulmonary fibrosis. sP-III-P has been radioimmunoassayed in an overall series of 57 patients and the levels were higher (19.18 +/- 9.17 ng/ml) than in 25 age- and sex-matched controls (11.32 +/- 2.15 ng/ml; p less than 0.001). The elevation was neither sex-related nor related to obvious liver sarcoid localization. Although sP-III-P levels were slightly higher in patients with stage II, there was no significant difference in patients with stage I or III. We found a positive relationship with serum angiotensin-converting enzyme (S-ACE) levels (p less than 0.04), but not with other markers of disease activity (67Ga uptake, bronchoalveolar lavage [BAL] lymphocyte percent, vital capacity, and lung diffusing capacity). The relationship with S-ACE was confirmed in a longitudinal follow-up study, where sP-III-P strictly paralleled the S-ACE behavior. Finally, the initial sP-III-P levels did not predict cases either with disease relapse or resistance to corticosteroid treatment. We conclude that, in our study, sP-III-P levels failed to characterize sarcoid patients with radiologic fibrotic pattern (stage III), and, in addition, were unable to predict which patients would have a poor prognosis. Rather, they reflect a metabolic activity of sarcoid granuloma cells. Thus, the usefulness of sP-III-P in the treatment of patients with sarcoid may be considered similar to that of S-ACE.

Spectrum of alveolitis in quartz-exposed human subjects

To characterize silica-induced alveolitis in human subjects, we studied 22 workers in the granite stone cutting industry of Quebec and compared results with those of 22 manual workers without quartz exposure (group 1). All were nonsmokers and were of comparable age. On the basis of chest roentgenogram, seven were without disease (group 2), nine had silicosis without coalescence/conglomeration (group 3), and six had silicosis with coalescence/conglomeration (group 4). The alveolitis in subsets of silica-exposed workers with distinct clinical stages of disease was found to have distinct biologic characteristics.