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

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.