대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Radiation pneumonitis after transarterial radioembolization (TARE)

Radiologic Findings

Figure 1. Chest PA shows GGO and consolidation in both lungs.
Figure 2-4. CT scans shows ground-glass opacification in both lungs with subpleural and perihilar sparing. Combined fibrotic change is also noted.

Brief Review

Transarterial radioembolization (TARE) is a technique for the treatment of hepatocellular carcinoma and liver metastases with catheter-directed intraarterial administration of yttrium-90 (90Y) resin or glass microspheres. Patients who are scheduled for this treatment all undergo initial evaluation to assess for tumor-induced arteriovenous shunting to the lung parenchyma (ie, hepatopulmonary shunting) with the use of intraarterial technetium-99m (99mTc) macroaggregated albumin (MAA) administration and quantitative scintigraphy. MAA can pass through tumor-associated arteriovenous shunts and become deposited in the pulmonary vasculature. If the hepatopulmonary shunt fraction is sufficiently large for 90Y microspheres, a dose-dependent radiation-induced pneumonitis may ensue. The clinical manifestation of radiation pneumonitis after TARE is nonspecific respiratory symptoms such as nonproductive, dyspnea and fever. And this symptoms and radiologic findings are usually developed 1~2months after treatment. As a result of hepatic arteriovenous shunting, the microspheres entered the pulmonary circulation causing radiation pneumonitis with a unique appearance on radiographs and CT scans in this patient. CT scans showed air-space consolidation radiation from the hila and becoming confluent just short of the lung periphery. The subpleural and perihilar areas are relatively spared. And discrete demarcation between the consolidation and the normal peripheral pulmonary parenchymal is apparent. These may resolve or progress toward localized fibrosis, traction bronchiectasis and focal honeycombing. Late complications include pneumothorax and superinfections. Corticosteroid therapy is the treatment of choice for radiation pneumonitis.

Please refer to

Case 877,

References

1. Wright CL, Werner JD, Tran JM, Gates VL, Rikabi AA, Shah MH, et al. Radiation pneumonitis following yttrium-90 radioembolization: case report and literature review. Journal of Vascular and Interventional Radiology. 2012;23(5):669-74.
2. Lin M. Radiation pneumonitis caused by yttrium-90 microspheres: radiologic findings. AJR American journal of roentgenology. 1994;162(6):1300-2.

Keywords

lung, radiation pneumonitis, radioembolization, HCC,