Парамагнітне контрастування пухлинних уражень легень пентамангом 1,0 М в експерименті
Objective: We have evaluated the image-enhancement properties of high-molar 1M solution of Manganese(II)-diethylentriaminpentaacetate (Pentamang 1M) as a paramagnetic contrast agent for detection of lung tumors, as well as tumor metastases, with T1-weighted MRI in dogs. Material and Methods: Pentamang 1M was obtained using original patented nanopowder technology from manganese dioxide or manganese carbonate and sodium diethylentriaminpentaacetate as described before (Beljanin e.a. 2008). Nine dogs were employed for the study, in all the lung tumor was suggested during routine veterinary clinical inspection and later on verified with ultrasonic study. MRI studies were carried out using low-field scanner (0,2 Т Magetom Open machine, by Siemens Medical Ltd, Germany) in Т1-and T2-weighted modes before and 7-12 min after injection of pentamang 1M. The standard dose of pentamang 1M was as high as 1 ml of solution per 10 kg of BW. The results were reported by noninformed radiologist and quantified using enhancement index(IE), as IE=(Intensity of T1-wMRI <sub>pentamang</sub>)/(Intensity of Т1-wMRI <sub>Initial</sub>). Results: In all dogs the primary tumor as well as metastatic foci were significantly enhanced by injection of pentamang 1M. In particular the enhancement was for various locations of tumor masses as high as follows. In primary tumor the IE = 1,52 ± 0,09; in metastases in ribs IE = 1,29 ± 0,07; in paratracheal lymphatic metastases IE = 1,48 ± 0,11; in paraaortic mets the IE = 1,37 ± 0,07; in pleural mets IE = 1,33 ± 0,09. No significant enhancement was seen in intact tissues, in particular in liver parenchyma, making evidence for stability of pentamng 1M. Nevertheless significant enhancement was observed in extumoral lung parenchyma, with IE= 1,23 ± 0,05, and also in myocardium, with IE = 1,15 ± 0,09. Conclusion: The pentamang 1M provides significant paramagnetic enhancement of both primary lung tumors and metastatic involvement of lymph nodes, and hencefore pentamang 1M is worth clinical testing as tumor imaging agent for chest MRI studies.