Value of technetium-99m diethyltriamine pentaaceticacid radioaerosol inhalation lung scintigraphy for the stage of amiodarone-induced pulmonary toxicity

BACKGROUND: Amiodarone is a potent antiarrhythmic agent that is limited in clinical use by its adverse effects, including potentially life threatening amiodarone-induced pulmonary toxicity (AIPT). The alteration of technetium-99m diethyltriaminepentaaceticacid (Tc-99m DTPA) radioaerosol lung clearance in AIPT was experimentally investigated. METHODS: Eighteen white New Zealand rabbits (initial weight 4.1+/-0.2 kg) were divided into two groups. AIPT group (n=13) was administered amiodarone (20 mg/kg BW) ip as a 5% aqueous solution for 6 week. The controls (n=5) were administered the same amount of 0.9% saline ip. Four rabbits of AIPT group died due to AIPT. The reminders of AIPT group (n=9) and controls underwent Tc-99m DTPA radioaerosol lung scintigraphy at the end of the treatment period. AIPT group was divided into two subgroups according to histopathologic evaluation. AIPT-I had interstitial pneumonitis (n=4) and AIPT-II had interstitial pneumonitis with fibrosis (n=5). RESULTS: The mean T(1/2) values of in control, AIPT-I, and AIPT-II groups were found 54+/-4.4, 39.2+/-11.7 and 114.6+/-16.7 min, respectively. The mean T(1/2) values of Tc-99m DTPA significantly differ than other groups (X(2)=11.78, P=0.02). The significantly increased T(1/2) values was noted in AIPT-II group when compared with control (P=0.001). In contrast, AIPT-I group has significantly lower T(1/2) values than control group (P=0.03). CONCLUSION: We suggested that Tc-99m DTPA radioaerosol inhalation lung scintigraphy provides an accurate evaluation about stage of lung toxicity and therefore may be a useful tool for the monitoring of AIPT.