Computed tomography of acute radiation nephritis

Abstract

A patient with Hodgkin's disease received a fractionated 3,740 rad dosage over 4 weeks to a portal that included both kidneys. Three months later a computed tomographic scan obtained 2 hours after intravenous contrast injection demonstrated sharply demarcated, dense, persistent nephrograms corresponding to the irradiated areas. These changes are ascribed to acute radiation nephritis, reflecting tubular stasis and ischemia.

“Segmental” prolonged cortical nephrogram as a result of radiation damage to the kidneys

“…However, the computerized tomographic (CT) appearance of this phenomenon has received little attention. The previously described appearance is a bilateral nephrographic abnormality involving the area of the kidneys included in the radiation field, usually the medial aspects [3,4]. We demonstrate a delayed nephrogram with prolonged corticomedullary differentiation.…”

“…Andersen et al described two cases of radiation nephritis with a decreased nephrogram in the affected areas [3], and Moore presented a single case with a focal delayed dense nephrogram following an initially normal appearance [4]. A prolonged corticomedullary differentiation was not noted.…”

FDG PET/CT Appearance of Radiation Nephritis

“…CT findings of radiation-induced changes in the kidneys have also been described. 3,[7][8][9] While the irradiated renal tissue shows low attenuation during the early nephrogram phase as noted in our case and those reported in the literature, 3 the delayed ceCT demonstrated persistent nephrogram in the irradiated regions with clearance of contrast from nonirradiated regions. 7,9 This persistent nephrogram resembles iFDG and the increased 99m Tc-MDP activity at 1 to 3 hours after injection.…”

“…3,[7][8][9] While the irradiated renal tissue shows low attenuation during the early nephrogram phase as noted in our case and those reported in the literature, 3 the delayed ceCT demonstrated persistent nephrogram in the irradiated regions with clearance of contrast from nonirradiated regions. 7,9 This persistent nephrogram resembles iFDG and the increased 99m Tc-MDP activity at 1 to 3 hours after injection. Given the similarities, it is conceivable that the accumulation of 99m Tc-MDP, FDG, and CT contrast in the irradiated region during the delayed phase may share a common mechanism, that is, delayed excretion from injured renal tissue as also suggested by some of these authors, 4,5 while there may be additional mechanisms for different compounds.…”