Detection of alveolar epithelial injury by Tc-99m DTPA radioaerosol inhalation lung scan in rheumatoid arthritis patients

Rheumatoid arthritis (RA) is a systemic autoimmune disorder primarily involving the joints. Lung alterations in RA may be primary or secondary to pharmacological treatments and may involve the alveoli, interstitium, airways and/or pleura. Technetium-99m diethylenetriaminepentaacetic acid (Tc-99m DTPA) aerosol inhalation scintigraphy is a sensitive and noninvasive test commonly employed to assess pulmonary epithelial membrane permeability. The purpose of the this study was a) to investigate the changes of pulmonary alveolar epithelial permeability in patients with RA, b) to determine the relationship between the clearance rate of Tc-99m DTPA and pulmonary function test (PFT) results, and c) to determine the relationship between the clearance rete of Tc-99m DTPA and clinical parameters of disease. Twenty-five patients with RA but without lung alterations were included in the study. The patients were 22 females, and 3 males; mean age 53.6 +/- 8.7 years. Technetium-99m DTPA aerosol inhalation scintigraphy was performed on the study and healthy control groups. Clearance half times (T1/2) were calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was calculated on the first-minute image. There were no significant differences in the mean T1/2 or mean PI values between the RA patients and control subjects. No correlation was found between the mean T1/2 values of Tc-99m DTPA clearance and activity of RA, clinical values, or the spirometric measurements except FEV1/FVC and functional status in RA patients (p = 0.02, p = 0.01, respectively). However, a weak correlation was found between duration of disease and T1/2 values of Tc-99m DTPA clearance (p = 0.006). PI values tended to correlate with FEF25-75, although, this was not statistically significant (p = 0.057). This study shows that no changes occur in alveolar-capillary permeability in RA patients without lung alterations.     

Using <Superscript>99m</Superscript>Tc-DTPA radioaerosol inhalation lung scan as compared with computed tomography to detect lung injury in blunt chest trauma

Background

Detection of pulmonary contusion in patients with blunt chest trauma is very important so as to commence therapy immediately to avoid irreversible damage. The purpose of our study was to evaluate the efficacy of technetium-99m diethylene triamine pentaacetic acid (^99mTc-DTPA) aerosol inhalation lung scintigraphy in comparison with chest computed tomography (CT) in the diagnosis of pulmonary contusion at acute blunt chest trauma.

Methods

Twenty-nine patients with isolated blunt chest trauma were referred to the emergency department of our hospital, and nine healthy people participated in this study. Sixteen patients who had pulmonary contusion on CT scans were referred to as group 1, and 13 patients who had normal CT scans as group 2. Nine healthy people comprised a control group. ^99mTc-DTPA aerosol inhalation lung scintigraphy was performed on the first day in all patients.

Results

The mean half time (T_½) and penetration index values of ^99mTc-DTPA clearance were significantly lower in groups 1 and 2 compared with the control group. Among the three groups, there were no significant differences in arterial blood gas analysis except for PO₂. The mean T_½ value of ^99mTc-DTPA clearance did correlate with PO₂ values but not with pH, PCO₂, or HCO₃ values.

Conclusions

^99mTc-DTPA radioaerosol inhalation lung imaging may serve as a useful adjunct and supportive method to chest CT scanning for detecting mild pulmonary contusion.

     

Impaired lung epithelial permeability in hepatitis C virus antibody positive patients detected by 99mTc-DTPA aerosol scintigraphy

Chronic hepatitis C virus (HCV) infection has been recently identified as an aetiological agent in idiopathic pulmonary fibrosis. The present study was designed to determine the pulmonary clearance rate of 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) in asymptomatic HCV antibody positive (HCV Ab+) patients and the role of 99mTc-DTPA aerosol scintigraphy in the early detection of lung involvement. Twenty-six non-smoker HCV Ab+ and HCV-RNA (+) patients (20 female, six male; aged 43+/-11 years), with no clinical pulmonary symptoms, and normal radiological findings, were studied. Thirty-one healthy non-smoker volunteers (24 female, seven male; aged 40+/-10 years) were taken as a control group. 99mTc-DTPA aerosol inhalation scintigraphy and pulmonary function tests were performed in all patients and in controls. On the basis of the scintigrams the percentage decline in activity per minute (Kep) was evaluated, which represented an accurate parameter of lung membrane permeability. The mean Kep values of healthy controls (0.78+/-0.13 for left lung, 0.79+/-0.14 for right lung) were significantly lower than HCV Ab+ patients (1.10+/-0.31 for left lung, 1.11+/-0.34 for right lung, P<0.001). But no significant change was observed in PFT (P>0.05). We conclude that subclinical alveolitis and/or interstitial lung disease may be present in patients with HCV Ab+, since it is known that an increase in the epithelial permeability of the lung is an early manifestation of interstitial disease.     

Evaluation of alveolar clearance by Tc-99m DTPA radioaerosol inhalation scintigraphy in welders

OBJECTIVES: The welding process produces metal fumes and gases which may affect respiratory health. Technetium-99m diethylenetriaminepentaacetic acid (Tc-99m DTPA) dynamic lung scanning is an easy, noninvasive method to assess disorders of alveolar-capillary barrier permeability secondary to epithelial damage. We aimed to investigate the alveolar clearance by Tc-99m DTPA radioaerosol inhalation scintigraphy in welders, to assess additive effects of exposure to welding fumes and cigarette smoking on clearance rate of alveolar epithelium and to determine the correlation between Tc-99m DTPA aerosol lung scintigraphy and spirometric measurements. METHODS: Nine nonsmoking welders, 9 smoking welders, and a control group of 6 nonsmokers and 6 smokers were accepted to the study. Tc-99m DTPA radioaerosol inhalation scintigraphy was performed in all subjects. Clearance half time (Tl/2) was calculated by placing a monoexponential fit on the curves. Penetration index (PI) was also calculated on the first minute image. Pulmonary function tests of welders and control group were compared. RESULTS: The mean T1/2 values of Tc-99m DTPA of the nonsmoking welders were significantly higher than those of the nonsmoking control group (82.1+/-24.3 min and 48.1+/-9.7 min, respectively; p = 0.003). The mean T1/2 values of Tc-99m DTPA of the smoking welders were higher than those of the smoking control group (53.3+/-24.5 min and 44.5+/-9.7 min, respectively; p = 0.510). PI of the nonsmoking welders was significantly higher than that of the nonsmoking control group (0.46+/-0.38 and 0.39+/-0.46 respectively; p = 0.004). PI of the smoking welders was significantly higher than that of smoking control group (0.43+/-0.38 and 0.37+/-0.45, respectively; p = 0.019). There was a negative correlation between T1/2 value and FEV1% (r = -0.468, p = 0.016), FVC% (r = -0.442, p = 0.024) and FEF25-75% (r = -0.391, p = 0.048) in the welders and control group. No statistically significant differences were found in the values of the standard pulmonary function tests of any of the subjects. CONCLUSIONS: Welding seems to decrease alveolar clearance which causes an increase in the penetration index. This was considered to be due to fibrotic changes and increased number of alveolar macrophages induced by welding fumes.     

Technetium-99m DTPA inhalation scintigraphy in patients treated with fluoxetine and maprotiline: preliminary results

Drug-metabolising enzymatic activities have been detected in tracheobronchiolar, bronchiolar and alveolar regions in the lungs. Induction of phospholipidosis by amine drugs such as clorphentermine has also been shown. This study aimed to investigate the effect of fluoxetine and maprotiline, which contain amine groups in their structure, on pulmonary epithelial membrane permeability. Twenty-seven patients (mean age 36+/-12 years) with various psychiatric problems, of whom 17 were treated with fluoxetine and 10 with maprotiline, were included in this study. Technetium-99m diethylene triamine penta-acetic acid (DTPA) aerosol inhalation scintigraphy was performed before and after 4-6 weeks of therapy. Following the inhalation of 1480 MBq 99mTc-DTPA for 3 min, lung images in a 64x64 matrix were obtained every minute for 30 min. Regions of interest were drawn around the periphery of the lungs and on the major airways. Clearance half-times (T 1/2) were calculated by placing a mono-exponential fit on the curves. Penetration index (PI) was calculated on the first-minute image. There was no difference between the clearance rates of 99mTc-DTPA before and after therapy for either the fluoxetine or the maprotiline group. After therapy, a significant decrease in PI was found in patients treated with fluoxetine (PI values before and after therapy: 0.53+/-0.03 and 0.49+/-0.05 respectively, P< or =0.05). This finding might have been due to the induction of increased synaptic serotonin (5-HT) by fluoxetine, which acts by inhibiting the re-uptake of 5-HT on presynaptic membranes. Bronchoconstriction of small and medium airways may be caused by direct and indirect effects of 5-HT on smooth muscle contraction.     

Alveolar epithelial permeability in patients with primary spontaneous pneumothorax as determined by Tc-99m DTPA aerosol scintigraphy

PURPOSE: Primary spontaneous pneumothorax (PSP) occurs subsequent to a disruption in the continuity of visceral pleura and escape of air into the pleural space. The cause of PSP is most often the rupture of subpleural blebs or bullae. It is usually difficult to detect evidence of pulmonary pathology. The purposes of the present study were (1) to investigate the changes of pulmonary alveolar epithelial permeability in patients with PSP as determined by Tc-99m DTPA aerosol lung scintigraphy, (2) to assess whether or not some differences exist between apical and basal parts of the lungs, and (3) to determine the relationship between the clearance rate of Tc-99m DTPA and the PFT results, the recurrence rate of PSP, and the percentage of pneumothorax in affected lung. MATERIAL AND METHODS: Thirteen PSP patients (two females, 11 males; mean age 32.5 +/- 11.8 years) with normal chest X-ray were studied. Thirteen healthy non-smoking volunteers (1 female, 12 males; mean age, 35.8 +/- 10 years) were selected as a control group. Tc-99m DTPA aerosol lung scintigraphy and PFT were performed in all patients and controls. Clearance rates (%/min) of Tc-99m DTPA aerosol in right and left lung field, and apical and basal parts of each lung were calculated from dynamic images for 15 min. RESULTS: There was no significant difference (p > 0.05) between patients and controls, or between apical and basal parts of each lung. No correlation was found between the clearance rate of Tc-99m DTPA and PFT results, the recurrence rate of PSP, or the percentage of pneumothorax. CONCLUSION: This study demonstrates that pulmonary epithelial permeability is not altered in PSP patients; the clearance rate of Tc-99m DTPA shows no difference between apical and basal parts of each lung.     

The bronchoalveolar epithelial permeability in house painters as determined by Tc-99m DTPA aerosol scintigraphy

PURPOSE: Isocyanates are highly reactive chemicals used in a number of industries including paints. Therefore, house painters are known to be at risk for occupational exposure to isocyanates. Our objectives in this study were: (1) to investigate the possible effects of isocyanate exposition on the bronchoalveolar epithelial permeability in house painters by using Tc-99m DTPA radioaerosol lung scintigraphy; (2) to assess whether or not some differences exist between asthmatic and non-asthmatic house painters, and (3) to determine the relationship between Tc-99m DTPA radioaerosol lung scintigraphy and the spirometric measurements, and the work duration of house painters. MATERIALS AND METHODS: Ten non-smoking house painters (28.8 +/- 8.8 yrs) and ten healthy volunteers underwent Tc-99m DTPA radioaerosol lung scintigraphy. Following inhalation of radiotracer through a nebulizer for 5 minutes, dynamic scintigrams (1 frame/min, up to 10 min) were taken from both lungs. ROI's were drawn over the both lung area, and time-activity curves were obtained, from which the half-time (T1/2) of Tc-99m DTPA clearance was calculated. Spirometric lung function test was measured in all house painters. RESULTS: Mean T1/2 values (min +/- SD) were 93.74 +/- 32.79 for house painters, and 90.96 +/- 40.02 for control subjects. There was no significant difference in T1/2 values of Tc-99m DTPA clearance between house painters and controls, and between asthmatic and non-asthmatic house painters as well. No correlation was observed between T1/2 values of Tc-99m DTPA clearance and spirometric measurements. In house painters, there was a positive correlation between T1/2 values of Tc-99m DTPA clearance and work duration (r = 0.73, p = 0.016). CONCLUSIONS: Our findings indicate that in house painters, occupational exposure to isocyanates has no effect on bronchoalveolar epithelial permeability, and the rate of Tc-99m DTPA clearance shows no difference between asthmatic and non-asthmatic house painters. The positive correlation between the rate of Tc-99m DTPA clearance and work duration needs to be confirmed in larger cohorts.     

Investigation of pulmonary epithelial permeability in patients after hyperbaric oxygen therapy by 99mTc diethylenetriaminepentaacetic acid aerosol inhalation lung scintigraphy

The aim of this study was to evaluate the possibility of pulmonary epithelial permeability damage in patients after hyperbaric oxygen therapy (HBOT) by 99mTc diethylenetriaminepentaacetic acid (99mTc-DTPA) aerosol inhalation lung scintigraphy. Twenty-five controls and 21 patients with normal chest X-rays and no cigarette smoking for at least 1 year were recruited for the study. 99mTc-DTPA aerosol inhalation lung scans were performed after 20 HBOT sessions in 21 patients with refractory osteomyelitis or diabetic foot. The HBOT with 100% oxygen at 2.5 atm absolute for 100 min was performed five times a week. Clearance rates (%/min) of 99mTc-DTPA aerosol in each lung field were calculated from the dynamic images for 30 min. Clearance rates of 99mTc-DTPA aerosol were compared between patients and controls by the unpaired t test. Thirteen patients who had 99mTc-DTPA aerosol lung scans before and after HBOT therapy studies were tested for statistical significance by using the paired t test. There was no statistically significant difference (P>0.05, unpaired t test) between patients and controls in every lung field. For the 13 patients who had 99mTc-DTPA aerosol studies both before and after 20 HBOT sessions, the results also showed no statistically significant difference (P>0.05, paired t test). It is concluded that there was no demonstrable pulmonary epithelial permeability change under current clinical HBOT protocol.     

Use of iodine-123 metaiodobenzylguanidine scintigraphy for the detection of amiodarone induced pulmonary toxicity in a rabbit model: A comparative study with technetium-99m diethyltriaminepenta acetic acid radioaerosol scintigraphy

The purpose of the study was; (i) to determine whether 123I-MIBG scintigraphy is sensitive for detection of amiodarone induced pulmonary toxicity (AIPT) and (ii) to compare it with 99mTc-DTPA radioaerosol. Twelve white New Zealand rabbit with initial mean body weight 4.24 +/- 0.47 g were divided into two groups. AIPT group (n = 7) was administered amiodarone (20 mg/kg BW). The control group (n = 5) received the same amount of 0.9% saline. All animals underwent 123I-MIBG and 99mTc-DTPA radioaerosol scintigraphy at the end of the treatment period. 123I-MIBG static thorax images were obtained during 10 minutes at 15 minutes and 3-hours after intravenous injection of the radiopharmaceutical. Lung to heart ratios (LHR) and lung to mediastinum ratios (LMR), and retention index (LRI) of 123I-MIBG were determined. Two days after 123I-MIBG scintigraphy, 99mTc-DTPA radioaerosol scintigraphy was performed, and clearance from the lungs was measured for 10 min (1 min/frame) following termination of inhalation. 123I-MIBG lung retention index (LRI) was significantly higher in the AIPT group than the control (61 +/- 4.6 vs. 40 +/- 4.5, p = 0.01). Early LHR and LMR were significantly lower in the AIPT group than in the control group (p = 0.04, p = 0.01, respectively), whereas those of late LHR and LMR were not significantly different. T1/2 values of DTPA clearance were significantly increased in AIPT group according to the control group (55 +/- 7.2 vs. 86.6 +/- 18.5, p = 0.02). 123I-MIBG scintigraphy is a valuable tool for detecting AIPT in a rabbit model. Additionally, 99mTc-DTPA radioaerosol scintigraphy is an excellent comprehensive investigational tool for detecting AIPT with the added advantage of lower cost.     

Pulmonary clearance of 99mTc-DTPA aerosol in patients with progressive systemic scleroderma]

Alveolar epithelial permeability was assessed in 32 patients with progressive systemic scleroderma (PSS), using 99mTc-DTPA aerosol. Immediately after the inhalation of 99mTc-DTPA aerosol for 3 to 6 minutes under normal tidal breathing, lung was imaged sequentially for 30 minutes from the posterior by a gamma camera and exponential fitting was processed on the time activity curve. T1/2 (min) was used as a parameter for the evaluation of permeability of alveolar epithelium. Patients with collagen disease showed shorter T1/2 (T1/2 = 43.7 +/- 23.8 min) than the normal volunteers (T1/2 = 76.8 +/- 8.7 min). No significant difference was observed between patients with or without interstitial changes on the chest CT. Significant correlation was not observed between T1/2 and %VC or %DLco. In 8 cases, studies were repeated in the interval of 3 to 19 months. Improvement of T1/2 was seen in 4 cases, independent of CT findings. These results suggest that 99mTc-DTPA aerosol clearance study provides information independent from other lung examinations, and may be useful for the assessment of lung interstitial changes in patients with PSS.     

Urine excretion of inhaled technetium-99m-DTPA: an alternative method to assess lung epithelial transport

Technetium-99m DTPA clearance (99mTc-DTPA) clearance measured by a gamma camera or a scintillation probe not only reflects epithelial transport, but is also influenced by an unknown amount of mucociliary clearance depending on particle size and aerosol deposition. This is confirmed by factor analysis of dynamic inhalation studies. Assessment of epithelial absorption by urinary excretion of inhaled 99mTc-DTPA is largely independent of aerosol lung deposition. Twenty-four-hour excretion reflects the amount of aerosol cleared by absorption, while two-hour excretion is a quantitative measure of the aerosol absorption rate from the epithelium into blood. Urinary 99mTc-DTPA excretion of two aerosols with different particle size correlated significantly (p less than 0.001) with analysis of lung clearance curves. A very similar regression in the form of a cumulative exponential function was found with both aerosols. Two-hour urine values of nonsmokers differed significantly from those of smokers or patients with active interstitial or infectious lung disease. This alternative procedure is suited as a bedside test and holds promise for patient monitoring and follow-up.     

Clearance of Tc-99m DTPA aerosol in mismatched and matched pulmonary perfusion defects

PURPOSE: To evaluate clearance changes of Tc-99m DTPA aerosol in mismatched and matched pulmonary perfusion defects. MATERIALS AND METHODS: Twenty-one patients (14 women, 7 men; mean age, 51 +/- 14 years) with possible pulmonary embolism were included in the study. On the day after perfusion (Q) scintigraphy with 5 mCi Tc-99m MAA, radioaerosol inhalation scintigraphy was performed using 45 mCi Tc-99m DTPA. Immediately and 45 minutes after the inhalation, early and delayed inhalation images (EI and DI, respectively) were obtained. Group 1 included 11 patients with mismatched defects who had a high probability of pulmonary embolism according to the Q/EI scan results. Group 2 included 10 patients with matched defects who had a low probability of PE. Contralateral normal lungs of 7 patients in group 2 served as controls (group 3). In groups 1 and 2, regions of interest were drawn over the mismatched and matched perfusion defects where they were best visualized, and this region of interest was mirrored to the same region on EI and DI images. For the control group, this was done in the contralateral normal lung. Mean counts in each region of interest were used for quantitative analysis, and the percentage clearance ratio was calculated using the following formula: early counts - late counts/early counts x 100. RESULTS: The average percentage clearances for the three groups were as follows: group 1, 37% +/- 10%; group 2, 21% +/- 4%; group 3, 24% +/- 7%. Differences between groups 1 and 3 were significant, as were those between groups 1 and 2 (P < 0.05). Patients with mismatched perfusion defects had increased DTPA clearance compared with the control group and those with matched defects. CONCLUSIONS: Vascular occlusion may lead to impairment of the alveolar-capillary barrier and consequently an increase in the clearance of Tc-99m DTPA aerosol in embolized regions. Immediately after inhalation, Tc-99m DTPA imaging should be started in the projection where perfusion defects are best seen to avoid potential misinterpretation of pulmonary embolism.     

Evaluation of the effects of toluene inhalation on alveolar epithelial permeability by 99mTc-DTPA inhalation scintigraphy in automobile painters

BACKGROUND: The main component of paint thinner used in industry is toluene diisocyanate (TDI) which can cause occupational asthma in 5-10% of exposed workers. AIM: To investigate the effect of TDI on 99mTc clearance rate of alveolar epithelium and on pulmonary function tests (PFT) in automobile painters, and to determine the relationship between 99mTc-DTPA radioaerosol lung scintigraphy and serum levels of antioxidant enzymes and metalloproteinases (MMPs) of automobile painters. METHODS: Twenty-eight automobile painters and 13 control subjects were included in the study. 99mTc-DTPA aerosol inhalation scintigraphy and PFT were administered to all subjects. Clearance half-time (T1/2) and penetration index (PI) on the first-minute image after 99mTc-DTPA scintigraphy were calculated. Blood levels of MDA, antioxidant enzymes and metalloproteinases were measured. RESULTS: The mean T1/2 values of automobile painters were longer in both smoker and non-smoker subjects, but the difference was not significant (P>0.05). Although the PFT values decreased in automobile painters, there was no significant difference between each group. Any correlation between spirometric measurements and T1/2 or PI values in non-smoking automobile painters was not detected. Negative correlation among mean T1/2 value and FVC% and FEV1% in smoking automobile painters, and positive correlation between mean T1/2 value and MMP-9, GSH-Px levels in non-smoking automobile painters were detected. CONCLUSION: Our results suggested that the clearance of 99mTc-DTPA from the lungs of automobile painters was slower than in the control group, but the difference is not statistically significant. This data also supports the observation that TDI occasionally stimulates bronchial changes rather than alveolar changes in automobile painters.     

Water-pipe smoking effects on pulmonary permeability using technetium-99m DTPA inhalation scintigraphy

OBJECTIVE: Although extensive work has been done on cigarette smoking and its effects on pulmonary function, there are limited number of studies on water-pipe smoking. The effects of water-pipe smoking on health are not widely investigated. The aim of this study was to determine the effects of water-pipe smoking on pulmonary permeability. METHODS: Technetium-99m DTPA inhalation scintigraphy was performed on 14 water-pipe smoker volunteers (all men, mean age 53.7 +/- 9.8) and 11 passive smoker volunteers (1 woman, 10 men, mean age 43.8 +/- 12). Clearance half-time (T 1/2) was calculated by placing a monoexponential fit on the time activity curves. Penetration index (PI) of the radioaerosol was also calculated. RESULTS: PI was 0.58 +/- 0.14 and 0.50 +/- 0.12 for water-pipe smokers (WPS) and passive smokers (PS) respectively. T 1/2 of peripheral lung was 57.3 +/- 12.7 and 64.6 +/- 13.2 min, central airways was 55.8 +/- 23.5 and 80.1 +/- 35.2 min for WPS and PS, respectively (p < or = 0.05). FEV1/FVC% was 82.1 +/- 8.5 (%) and 87.7 +/- 6.5 (%) for WPS and PS, respectively (0.025 < p < or = 0.05). CONCLUSIONS: We suggest that water-pipe smoking effects pulmonary epithelial permeability more than passive smoking. Increased central mucociliary clearance in water-pipe smoking may be due to preserved humidity of the airway tracts.     

Tc-99m HMPAO scintigraphy in amiodarone-induced acute lung toxicity: comparison with Tc-99m DTPA inhalation scintigraphy

PURPOSE: This case demonstrates the use of Tc-99m HMPAO scintigraphy in amiodarone (AD)-induced lung toxicity. The aim of this presentation is also to discuss different scintigraphic modalities in the diagnosis and follow up in AD-induced lung toxicity. MATERIALS AND METHODS: A 77-year-old man, with a suspicious AD-induced acute lung toxicity, underwent Tc-99m DTPA aerosol inhalation scintigraphy and Tc-99m HMPAO scintigraphy. RESULTS: Rapid alveolar clearance of Tc-99m DTPA was found during AD therapy and increased lung uptake of Tc-99m HMPAO was also demonstrated. These findings supported the diagnosis AD lung toxicity. After cessation of therapy, Tc-99m DTPA alveolar clearance was decreased. Although there was some decrease in L/H and L/B ratios of Tc-99m HMPAO after 3 weeks of stopping therapy, Tc-99m HMPAO uptake in the lungs was still continued. This finding may be the result of ongoing pulmonary inflammation as a result of the long half-life of AD. CONCLUSION: Compared with Tc-99m DTPA aerosol inhalation scintigraphy, Tc-99m HMPAO scintigraphy may have a role in the diagnosis of AD lung toxicity. Nevertheless, there is a need for longitudinal studies investigating patients under AD therapy using follow-up Tc-9m HMPAO scintigraphy.     

Technetium-99m-DTPA aerosol scintigraphy in amiodarone induced pulmonary toxicity in comparison with Ga-67 scintigraphy

Amiodarone hydrochloride, which is used in life-threatening cardiac tachyarrhythmia, has been known to cause amiodarone induced pulmonary toxicity (AIPT) as a complication. In this study we aimed to investigate the clinical value of technetium-99m diethylene triamine penta-acetic acid (DTPA) aerosol lung scintigraphy in patients with AIPT in comparison with gallium-67 (Ga-67) scan. The study group included 26 cases, 7 patients with diagnosis of AIPT (Group A), 8 patients receiving amiodarone therapy but without AIPT (Group B) and 11 healthy subjects as a control group (Group C). All patients underwent Ga-67 and Tc-99m-DTPA aerosol scintigraphy in addition to various laboratory tests, Ga-67 scintigraphy was positive in 4 of 7 AIPT patients but quite normal in Group B. A positive correlation was found (r = 0.52, p < 0.05) between kep values determined by Tc-99m-DTPA aerosol scintigraphy and the cumulative dose of amiodarone. The mean kep values were 2.04% +/- 0.85%/min, 1.30% +/- 0.42%/min and 0.86% +/- 0.19%/min for groups A, B and C, respectively. The mean clearance rate of group A was significantly faster than that of normals (p < 0.0005) and group B (p = 0.028). In addition, there was a significant difference between groups B and C (p = 0.015). In conclusion, Ga-67 lung scintigraphy is a useful method for the detection of AIPT but Tc-99m-DTPA aerosol scintigraphy offers better results than Ga-67 scintigraphy. Early changes in Tc-99m-DTPA clearance may be observed in patients receiving amiodarone. The kep value in patients with AIPT is noticeably increased with respect to the control group. With its favorable physical properties, low cost, lower radiation burden and its ability to be used as an objective measure for the pulmonary clearance rate, Tc-99m-DTPA aerosol scintigraphy appears to be promising in patients receiving amiodarone therapy.     

Pulmonary clearance of 99mTc-HMPAO aerosol

The clearance rate of inhaled aerosols of a lipophilic substance, 99mTc-HMPAO (Hexamethyl propylene amine oxime) was studied and compared to that of hydrophilic substances in 6 normal volunteers and 18 patients with lung diseases. The subject in sitting position inhaled a single deep breath of 99mTc-HMPAO aerosols, and held his breath about 30 sec. Then he continued to breath aerosols again for about 3 min. Radioactivity rapidly falls down during breath holding, to about 60% of the peak value (fast phase), with T 1/2 of 3.75 +/- 2.22 sec in 6 normal volunteers. This rapid phase was not appeared in hydrophilic aerosols with 99mTc-DTPA and 99mTc-pertechnetate and in lipophilic aerosol with 123I-IMP aerosol. The clearance of residual activity of 99mTc-HMPAO was slow with T 1/2 of 17.4 +/- 4.0 min. The T 1/2 of 99mTc-DTPA, 99mTc-pertechnetate and 123I-IMP were 50.2 +/- 20.9 min, 11.4 +/- 4.3, and 62.5 +/- 20.8 min respectively. 99mTc-HMPAO may cross transcellularly using the whole alveolar surface. The clearance of aerosols in the fast phase is rapid and depend on the regional perfusion. On the other hand, hydrophilic aerosol pass by an intercellular pathway and the clearance will be diffusion limited. As conclusion, inhalation study of 99mTc-HMPAO might be a new method to evaluate perfusion following ventilation study.     

Technetium-99m DTPA aerosol and gallium scanning in acquired immune deficiency syndrome

In 11 non-smoking AIDS patients suspected of pneumocystis carinii pneumonia (PCP), the results of Tc-99m DTPA aerosol clearances, gallium scans, and arterial blood gases were compared with those of bronchoalveolar lavage (BAL). Nine patients had PCP. All had increased clearances five times higher than the normal (5.6 +/- 2.3% X min-1 vs 1.1 +/- 0.34% X min-1, N = 10, P less than 0.001), suggesting an increased alveolar permeability. Gallium scans were abnormal in six patients but normal or slightly abnormal in the three others. Four of these nine patients had normal chest x-rays. In two of these the gallium scan was abnormal, but in the two others, only the increased Tc-99m DTPA clearances showed evidence of lung disease. Two patients had normal BAL, with normal clearances and gallium scans. Four out of the nine patients with PCP were studied after treatment. Three recovered and had normal clearance and gallium scans. One still had PCP with increased clearance but normal gallium scan. Gallium scanning and Tc-99m DTPA clearance are useful for detecting lung disease in AIDS patients with suspected PCP and for prompting BAL when chest x-rays and PaO2 levels are normal. Due to its high sensitivity, a normal Tc-99m DTPA clearance could avoid BAL.     

Technetium-99m-DTPA aerosol and gallium-67 scanning in pulmonary complications of human immunodeficiency virus infection.

We retrospectively compared the results of 67Ga chest scans and 99mTc-DTPA aerosol clearance measurements with those of fiberoptic bronchoscopy in 88 patients infected with the human immunodeficiency virus. Of 100 investigations, a pulmonary infection was diagnosed in 39, mainly Pneumocystis carinii pneumonia and a noninfectious disorder was found in 42, mainly Kaposi's sarcoma and lymphocytic alveolitis. Gallium scans and DTPA clearance were abnormal respectively in 74% and 92% of infectious complications, and in 12% and 60% of noninfectious disorders. In 10 cases, DTPA clearance was accelerated, while chest x-ray, arterial blood gases and even gallium scanning were normal. A value of DTPA clearance greater than 4.5%.min-1 was both sensitive and specific for the diagnosis of Pneumocystis carinii pneumonia. The gallium scan was always normal in bronchopulmonary Kaposi's sarcoma. We conclude that in symptomatic patients: (1) DTPA clearance measurements are useful for detecting lung disease when chest x-ray and/or PaO2 are normal and (2) a gallium scan is indicated to distinguish progressive Kaposi's sarcoma from a superimposed second process when radiological abnormalities of pulmonary Kaposi's sarcoma are present.     

SPECT images after intravenous injection of 99mTc-DTPA in lung tumors--comparison with delayed 123I-IMP lung scintigraphy

The aim of this study was to assess the efficacy of SPECT imaging of the thorax with 99mTc-DTPA, which accumulates at sites of increased capillary permeability and expanded extracellular space, by comparing it with delayed 123I-IMP lung scintigraphy. We have previously reported that increased uptake on delayed 123I-IMP lung scintigraphy was associated with atelectasis and inflammation. Thirteen patients with lung cancer (4 with atelectasis and 3 with pleurisy), one patient with malignant lymphoma complicated by pneumonia and pleurisy, and one patient with pneumonia were studied. 99mTc-DTPA scintigraphy was performed twice, 20-160 minutes and 2-4 hours after the intravenous administration of 370 MBq of 99mTc-DTPA. 123I-IMP scintigraphy was performed 24 hours after the intravenous injection of 111 MBq of 123I-IMP. SPECT images were obtained with both types of scintigraphy. 99mTc-DTPA scintigraphy was compared with 123I-IMP scintigraphy for its ability to detect atelectasis and pneumonia. All patients showed increased accumulation corresponding to the lesions on both 123I-IMP and 99mTc-DTPA scintigraphy. 123I-IMP scintigraphy showed a defect corresponding to the tumor with increased accumulation around the tumor, whereas 99mTc-DTPA scintigraphy showed accumulation corresponding to the tumor. Ten of 11 tumors showed accumulation of an intensity equal to that of the soft tissue of the chest wall on 20-60 min 99mTc-DTPA images. The 2-4 hr images showed that 99mTc-DTPA leaked from the periphery of the tumor toward its center. All the patients with pleurisy showed increased accumulation in effusion on 2-4 hr 99mTc-DTPA scintigraphy.(ABSTRACT TRUNCATED AT 250 WORDS)