MR evaluation of intrapulmonary hematoma.

We report a case of circumscribed intrapulmonary hematoma, in which MR findings were useful in establishing the diagnosis. It is usually easy to make a diagnosis of intrapulmonary hematoma using conventional methods, when clinical history of trauma and regression of the mass can be observed on serial radiography. However, in this case the mass remained almost unchanged 4 months after trauma on chest radiography and CT. Magnetic resonance revealed a hyperintense mass with an even higher signal rim on T1-weighted imaging and an irregular hyperintense mass on T2*-weighted imaging. We made a diagnosis of pulmonary hematoma based on these MR findings. Follow-up chest radiography and CT taken 1 year after the injury, revealed a substantial decrease in the size of the mass, which confirmed the diagnosis. As in this case, some intrapulmonary hematomas regress very slowly or may even increase in size, and diagnosis can be difficult with conventional methods. In such cases, MRI can be helpful.