Increased lung uptake of technetium-99m hexamethylpropylene amine oxime in systemic lupus erythematosus

Role of glutathione in lung retention of 99mTc-hexamethylpropyleneamine oxime in two unique rat models of hyperoxic lung injury

Rat exposure to 60% oxygen (O(2)) for 7 days (hyper-60) or to >95% O(2) for 2 days followed by 24 h in room air (hyper-95R) confers susceptibility or tolerance, respectively, of the otherwise lethal effects of subsequent exposure to 100% O(2). The objective of this study was to determine if lung retention of the radiopharmaceutical agent technetium-labeled-hexamethylpropyleneamine oxime (HMPAO) is differentially altered in hyper-60 and hyper-95R rats. Tissue retention of HMPAO is dependent on intracellular content of the antioxidant GSH and mitochondrial function. HMPAO was injected intravenously in anesthetized rats, and planar images were acquired. We investigated the role of GSH in the lung retention of HMPAO by pretreating rats with the GSH-depleting agent diethyl maleate (DEM) prior to imaging. We also measured GSH content and activities of mitochondrial complexes I and IV in lung homogenate. The lung retention of HMPAO increased by ≈ 50% and ≈ 250% in hyper-60 and hyper-95R rats, respectively, compared with retention in rats exposed to room air (normoxic). DEM decreased retention in normoxic (≈ 26%) and hyper-95R (≈ 56%) rats compared with retention in the absence of DEM. GSH content increased by 19% and 40% in hyper-60 and hyper-95R lung homogenate compared with normoxic lung homogenate. Complex I activity decreased by ≈ 50% in hyper-60 and hyper-95R lung homogenate compared with activity in normoxic lung homogenate. However, complex IV activity was increased by 32% in hyper-95R lung homogenate only. Furthermore, we identified correlations between the GSH content in lung homogenate and the DEM-sensitive fraction of HMPAO retention and between the complex IV/complex I activity ratio and the DEM-insensitive fraction of HMPAO retention. These results suggest that an increase in the GSH-dependent component of the lung retention of HMPAO may be a marker of tolerance to sustained exposure to hyperoxia.

Tc-99m HMPAO Scintigraphy in Amiodarone-Induced Acute Lung Toxicity

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.

Objective and noninvasive detection of sub-clinical lung injury in breast cancer patients after radiotherapy

AIMS

We employed technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) lung scan to detect sub-clinical lung injury after radiation therapy of 60 female patients diagnosed with right breast cancer.

METHODS

The degree of pulmonary vascular endothelium damage was represented as lung/liver uptake ratios (L/L ratios) calculated on Tc-99m HMPAO lung scan. All patients underwent simple mastectomy and post-operative radiotherapy of approximately 50 Gy. We divided the patients into three groups according to the interval between radiotherapy and lung Tc-99m HMPAO lung scan: Group 1 included 20 patients who received the lung scan within 1-3 months after radiotherapy, group 2 included 20 patients were within 3-9 months after radiotherapy, and group 3 included 20 patients were more than 9 months after radiotherapy. In addition, 20 age-matched normal women were included as the control group.

RESULTS

The L/L ratios were 0.32+/-0.04 for normal controls, 0.59+/-0.10 for group 1, 0.55+/-0.07 for group 2, and 0.34+/-0.04 for group 3, respectively. Based on our preliminary results, we found that sub-clinical lung injury and significantly increased L/L ratio in breast cancer patients received radiotherapy may occur within the first 6 months after radiotherapy. However, the L/L ratio is markedly decreased after 9 months.

CONCLUSION

Our findings concluded that the degree of pulmonary vascular endothelium damage represented as the L/L ratio on Tc-99m HMPAO lung scan has the potential to be a sensitive, objective and noninvasive method to detect sub-clinical lung injury in breast cancer patients received radiotherapy.

Comparison of quantitative 99mTc-HMPAO and 67Ga citrate lung scans in patients with active diffuse infiltrative lung disease

Diffuse infiltrative lung disease (ILD) is a heterogeneous group of disorders that predominantly affect the lung parenchyma and spare the airway. To objectively assess the degree of pulmonary vascular endothelium damage in active ILD, lung/liver uptake ratios (L/L ratios) on 99mTc hexamethylpropylene amine oxime (99mTc-HMPAO) lung scans were determined in 21 patients with active ILD. Meanwhile, the 67Ga citrate uptake index (GUI) on 67Ga lung scans was measured in order to evaluate the severity of lung inflammation in active ILD. The results show there were statistically significant differences between normal controls and patients with active ILD, as shown in the L/L ratio and GUI. However, when the patients were divided into two groups: (1) eight patients with normal chest X-ray findings, and (2) 13 patients with abnormal X-ray findings, there was no significant difference between groups 1 and 2 for the results of L/L ratio and GUI. In addition, no correlation between the degree of damage to the pulmonary vascular endothelium and the severity of lung inflammation was found. In conclusion, L/L ratios on 99mTc-HMPAO lung scans and GUI on 67Ga lung scans are different to the findings of chest X-rays and have the potential to objectively detect the degree of damage to the pulmonary vascular endothelium and the severity of lung inflammation in active IDL. However, the relationship between L/L ratio and GUI in active ILD is not significant.

Usefulness of techntium-99m hexamethylpropylene amine oxime lung scan to detect subclinical lung injury in patients with noninsulin-dependent diabetes mellitus

In this study, we employed techntium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) lung scan to detect subclinical lung injury of patients with noninsulin-dependent diabetes mellitus (NIDDM) who had normal chest X-ray findings (CXR) and pulmonary function test (PFT). The degree of pulmonary vascular endothelium damage was represented as lung/liver uptake ratios (L/L ratios) calculated by Tc-99m HMPAO lung scan. The L/L ratios of the 20 male NIDDM patients with normal CXR and PFT were compared with those of the 20 male normal controls. The results show that the L/L ratios on Tc-99m HMPAO lung scan were significantly higher in NIDDM patients than those in normal controls. Using a cutoff value of 0.50, 17 of the 20 (85%) NIDDM patients had abnormally increased L/L ratios. Our findings concluded that the pulmonary vascular endothelium damage represented as significantly increased L/L ratios on Tc-99m HMPAO lung scan in NIDDM patients with normal CXR and PFT. In addition, Tc-99m HMPAO lung scan has the potential to be a sensitive, objective, and noninvasive method to detect subclinical lung injury of patients with NIDDN, which are different from the traditional studies such as CXR or CFT.

Usefulness of technetium-99m hexamethylpropylene amine oxime lung scan to detect inhalation lung injury of patients with pulmonary symptoms/signs but negative chest radiograph and pulmonary function test findings after a fire accident--a preliminary report

OBJECTIVE

In this study, we employed technetium-99m hexamethylpropylene amine oxime (99mTc HMPAO) lung scan to detect inhalation lung injury of patients after a fire accident.

METHODS

Ten healthy men for controls and 10 male patients with pulmonary symptoms/signs from a fire accident were enrolled in this study for comparison. 99mTc HMPAO lung scan was performed in each control and patient, as well as the degree of pulmonary vascular endothelium damage was represented as lung/liver uptake ratios (L/L ratio). All of the controls and patients had no smoking histories. None of the controls and patients had positive findings of plain chest radiograph (CXR) and pulmonary function test (PFT).

RESULTS

The results showed that significantly higher L/L ratio in the 10 patients (0.53 +/- 0.07) than in the 10 controls (0.30 +/- 0.07) (the p value < 0.05). Using a cut-off value of 0.40, all of the 10 patients had abnormally increased L/L ratios.

CONCLUSIONS

We conclude that 99mTc HMPAO lung scan has the potential to be a sensitive, objective and noninvasive method to detect inhalation lung injury of patients with pulmonary symptoms/signs but negative CXR and PFT findings after a fire accident.

A pilot trial of quantitative Tc-99m HMPAO and Ga-67 citrate lung scans to detect pulmonary vascular endothelial damage and lung inflammation in patients of collagen vascular diseases with active diffuse infiltrative lung disease

Diffuse infiltrative lung disease (ILD) includes a heterogeneous group of disorders predominantly affecting lung parenchyma and sparing the airway. To assess the degree of pulmonary vascular endothelial damage in active ILD, lung/liver uptake ratios (L/L ratio) on technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) lung scan were determined in 30 patients with active ILD. Meanwhile, the gallium-67 citrate (Ga-67) uptake index (GUI) on Ga-67 lung scan was used to evaluate the severity of lung inflammation in active ILD. In this study, high-resolution CT (HRCT) was used to evaluate disease activity in ILD. The results show statistically significant differences between normal controls and patients with active ILD as shown in L/L ratios and GUI. However, when the patients were divided into two groups of 15 patients with normal chest X-ray findings and 15 with abnormal X-ray findings, there was no significant difference in those parameters. In addition, there was no statistically significant difference between the groups in HRCT scoring. No good correlation between the degree of pulmonary vascular endothelial damage and the severity of lung inflammation was found. In addition, there were no good correlations between HRCT scoring vs GUI and HRCT vs L/L ratio in different study subgroups. In conclusion, L/L ratios on Tc-99m HMPAO and GUI on Ga-67 lung scans differ from chest X-ray findings and have the potential to detect the degree of pulmonary vascular endothelial damage and severity of lung inflammation in active IDL. However, the relationships between HRCT scoring, GUI, and L/L ratio in patients with collagen vascular diseases and active ILD are not significant.

Increased lung uptake of technetium-99m hexamethylpropylene amine oxime in diffuse infiltrative lung disease

BACKGROUND

Diffuse infiltrative lung disease (ILD) is a heterogeneous group of disorders which predominantly affect the lung parenchyma and spare the airway.

OBJECTIVE

To assess pulmonary vascular endothelium damage in ILD, the lung uptake of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) was determined.

METHODS

In 20 ILD patients and 25 controls without ILD, the lung uptake of 99mTc-HMPAO was measured. Anterior lung imaging, including a large part of the liver, was made 10 min after intravenous injection of 20-25 mCi of 99mTc-HMPAO. Regions of interest covered the liver and lung to calculate the lung/liver uptake ratios. The 20 ILD patients included 10 patients with clinically manifest pulmonary disease (group 1) and 10 asymptomatic patients (group 2). All of the study subjects had normal pulmonary function test results.

RESULTS

The mean lung/liver uptake ratio in the 25 controls without ILD (0.36 +/- 0.10) was significantly lower than that in the 20 ILD patients (0.97 +/- 0.61). In addition, the mean lung/liver uptake ratio in the 10 ILD patients with clinically manifest pulmonary disease (1.45 +/- 0.51) was higher than that of the other 10 asymptomatic ILD patients (0.49 +/- 0.09).

CONCLUSIONS

Our results indicated that determining the lung/liver uptake ratio on 99mTc-HMPAO lung imaging should be an objective method to assess subclinical pulmonary damage in ILD patients.

Usefulness of technetium-99m hexamethylpropylene amine oxime lung scan to detect subclinical lung injury in patients with chronic renal failure

We used technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) lung scan to detect subclinical lung injury in patients with chronic renal failure (CRF), on regular hemodialysis (HD), who had normal chest X-ray findings (CXR) and pulmonary function test (PFT). The degree of pulmonary vascular endothelium damage was represented as lung/liver uptake ratios (L/L ratios) calculated by Tc-99m HMPAO lung scan. The L/L ratios of the 20 male CRF patients on HD with normal CXR and PFT were compared with those of the 20 male normal controls. The results show that the L/L ratios on Tc-99m HMPAO lung scans were significantly higher in CRF patients on HD (1.06 +/- 0.55) than those in normal controls (0.34 +/- 0.09). Using a cut-off value of 0.50, 18/20 [90%] CRF patients had abnormally increased L/L ratios. Our findings concluded that the pulmonary vascular endothelium damage represented as significantly increased L/L ratios on Tc-99m HMPAO lung scan in CRF patients on HD with normal CXR and PFT. In addition, Tc-99m HMPAO lung scan has the potential to be a sensitive, objective and noninvasive method to detect subclinical lung injury of CRF patients on HD, which is different from the traditional studies such as CXR or PFT.

Usefulness of quantitative Tc-99m HMPAO and Ga-67 citrate lung scans in detecting pulmonary vascular endothelium damage and lung inflammation in patients with systemic lupus erythematosus: a preliminary report

Pulmonary vascular endothelium damage in 34 patients with systemic lupus erythematosus (SLE) was measured by technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) lung scan. The degree of damage was represented as lung/liver uptake (L/L) ratio. The patients were divided into two subgroups according to the following criteria: (a) clinical features, separated as stable or flare stage and (b) chest X-ray findings separated as positive or negative results. Meanwhile, quantitative gallium-67 citrate (Ga-67) lung scan was performed as Ga-67 uptake index (GUI) to evaluate the severity of inflammation in the SLE lungs. The results show (a) no significant statistical differences in the degree of pulmonary vascular endothelium damage (the L/L ratio on Tc-99m HMPAO lung scan) between the two subgroups according to clinical features or chest X-ray findings and (b) no good correlation between the degree of pulmonary vascular endothelium damage and lung inflammation (GUI on Ga-67 lung scan). In conclusion, the change in pulmonary vascular endothelium damage in SLE may be unrelated to the clinical presentation or chest X-ray findings, and its degree is not related to the severity of pulmonary inflammation.