CT And MR Imaging Appearance Of Radiation Induced Liver Injury After Conformal Radiation Therapy

objective To search for the appearance of radiation induced liver injury (RILI)in CT and MRI after conformal radiation therapy(CRT),by which,RILI was different from recurrence of liver cancer after CRT.Materials and methods 34 patients with single liver carcinoma were treated with conformal radiation therapy with a total dose of 36-50Gy for 8-14 times. 1 to 3 months later.CT scan was performed in 31 patients,in which,plain CT scan(PCT)was performed in 21 patients,three-phase contrast enhancement scan(CECT)was performed in 8 patients,and 2 patients were checked by PCT and CECT at the same time .6 patients was checked by MR Imaging,3 of which were checked by CT scan.Difference of TDF value between no change and abnormal image in CT was tested by rank sum test. Results Regional atrophy of radiated liver was observed in 12 patients,in which,two was detected by MR imaging,others were detected by CT scan.Low density appeared in 15 patients in PCT.The type I appearance with no enhancement in the high dose region existed in 6 studies,type II with low density in artery phase.and high density in portal vein phase or prolonged phase existed in2 studies,and type III with persistent high density from artery phase to prolonged phase in 2 studies.In MR imaging,low signal or isosingal appeared in T1 weighted imaging,iso-signal or slightly high signal appeared in T2 weighted imaging. Signal become higher and higher in contrast enhancement imaging,and enhanced reticulate singal would appear. TDF value of radiation dose between no change and abnormal image in CT scan was different statistically (P<0.01) .Conclusions After conformal radiation therapy.Low density or isodensity existed in CT scan,low or isosignal in TI weighted MR imaging,and iso- or slightly high signal in T2 weighted MR imaging in post-radiated liver parenchyma around tumor,respectively.If high density or signal was observed in contrast enhancement imaging,a kind of gradual or persistant intensification pattern should appear,and in MR imaging, enhanced reticulate singal would appear.TDF value in abnormal CT image group was different from that in no chang group.