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

Assessment of lung toxicity caused by bleomycin and amiodarone by Tc-99m HMPAO lung scintigraphy in rats

AIM

The purpose of the study was to determine the lung toxicity caused by amiodarone (AD) and bleomycin (BLM) in rats, by means of Tc-99m HMPAO lung scintigraphy.

METHODS

Thirty albino rats were randomly divided into five groups. After AD or BLM was dissolved with isotonic saline (SF), a 0.5 ml solution was applied to the right bronchus via a catheter. Group 1 (n = 5 rats) received a single dose of AD, group 2 (n = 5) received two doses of AD, group 3 (n = 9) received BLM, group 4 (n = 3) received hydrochloric acid (HCl), and group 5 (n = 8) received SF. Rats in groups 1, 2, 3 and 5 were given 37 MBq Tc-99m HMPAO from the tail vein on days 7, 14, 21 and 28, and at 4 and 24 h in group 4. Static images of 10 min duration were obtained at 30 and 60 min by a double-headed gamma camera (Infinia, GE, Tirat Hacermel, Israel) on 256 × 256 matrix. Regular regions of interests were drawn over the right lung (RL), left lung (LL) and the liver (Li), and lung/liver (L/Li) ratios were calculated. After the scintigraphic imaging procedures were completed, rats were killed. Lung tissues were evaluated on a scale of (+) to (+++++) for edema, alveolar structural integrity and infiltration by inflammatory cells.

RESULTS

Groups 2 and 3 showed statistically significant differences in RL/Li and LL/Li ratios, whereby RL/Li was higher than LL/Li (p < 0.05). There were no significant differences in RL/Li and LL/Li ratios in group 5 (p > 0.05). In histopathological examination, minimal damage or artifacts were observed in group 5. In group 4, almost all pathological findings were present in the right lung. Statistically significant (p < 0.01) histological differences were found when groups 1 and 5 were compared. More significant (p < 0.001) pathological effects were noted when groups 2 and 3 were compared to both groups 5 and 1. Injury was more prominent in the lung tissues of the control rats that were given HCl. Increased RL/Li ratios and histopathological findings were consistent.

CONCLUSION

Tc-99m HMPAO lung scan are found to be useful in the identification of patients with lung toxicity. The simplicity of the procedure and lower radiation exposure are the advantages of Tc-99m HMPAO lung scan.

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.

Respiratory changes in a murine model of spontaneous systemic lupus erythematosus

The pathophysiology of systemic lupus erythematosus (SLE) has been very well described in many organs. However, the relation between extracellular matrix changes and lung dynamic mechanical behaviour deserves elucidation. To that end, pulmonary mechanics, lung morphometry and the amount of collagen and elastic fibres in the alveolar septa were analysed in mice with SLE [NZB/W (New Zealand Black/White) F1] and non-diseased NZW mice (control). Static (E(st)) and dynamic (E(dyn)) elastances, difference between dynamic and static elastances (DeltaE), airway resistance (R(aw)) and viscoelastic/inhomogeneous pressure (DeltaP(2)) were determined by the end-inflation occlusion method. Lungs were removed and prepared for histology. E(st), E(dyn), DeltaE and DeltaP(2) were higher in SLE than in control group, while R(aw) was similar in both groups. SLE group showed alveolar collapse and increased amount of elastic and collagen fibres. In conclusion, SLE mice showed an increase in elastic and viscoelastic/inhomogeneous pressures that was accompanied by deposition of collagen and elastic fibres in the alveolar septa.