Perfusion characteristics of radiation-injured lung on Gd-DTPA-enhanced dynamic magnetic resonance imaging.
OBJECTIVE
A contrast-enhanced dynamic magnetic resonance (MR) study was performed experimentally and clinically to describe perfusion characteristics of radiation-injured lung according to pathologic phases.


METHODS
The MR study was performed before and at 0.5, 1, 2, 3, 4, and 7 months after 40 Gy-dose irradiation to the right hemithorax in 8 dogs, and clinically in 12 lung lesions of 9 patients with acute or fibrotic radiation pneumonitis. Altered Gd-DTPA kinetics in the affected lungs was assessed by time-signal intensity curves. MR findings were correlated with lung histology and CT images.


RESULTS
Within 1 month after irradiation, the irradiated animal lungs showed focal and persistent contrast enhancement relative to nonirradiated lungs. This abnormality was pronounced during the next 2 months. After 4 months, irradiated lungs conversely showed lower enhancement during the Gd-DTPA first-pass but were followed by persistently greater enhancement during Gd-DTPA redistribution phase. Similar differences in enhancement abnormalities between acute and fibrotic radiation pneumonitis were clinically observed.


CONCLUSIONS
These findings indicate that Gd-DTPA kinetics can be altered according to the histopathologic change in early/acute radiation pneumonitis and radiation fibrosis and that the contrast-enhanced perfusion MRI may help differentiate the phases of radiation pneumonitis.
Department of Radiology, Yamaguchi University School of Medicine, Ube, Japan. nogasawa@po.cc.yanaguchi.ac.jp
Nobuhiko
N
Ogasawara
Kazuyoshi
K
Suga
Yuichi
Y
Karino
Naofumi
N
Matsunaga
D000368:Aged; D000818:Animals; D003287:Contrast Media; D004285:Dogs; D019786:Gadolinium DTPA; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008279:Magnetic Resonance Imaging; D011833:Radiation Injuries, Experimental / Q000175:diagnosis*; D017564:Radiation Pneumonitis / Q000175:diagnosis*
D003287:Contrast Media; D019786:Gadolinium DTPA