Bone Marrow Involvement by Small Cell Lung Cancer Demonstrated by Magnetic Resonance Imaging

Abstract

The detection of bone marrow involvement might have prognostic value and may influence therapeutic decisions in small cell lung cancer. In 15 patients with small cell lung cancer, bone marrow was evaluated with bone scintigraphy, magnetic resonance (MR) imaging, and aspiration biopsy of the sternum to detect bone marrow involvement. By bone marrow aspiration biopsy from the sternum, evidence of bone marrow metastases was seen in 7%(1/15) of patients with this disease. Skeletal scintigraphy showed bone marrow involvement in 7%(1/15) as well, hence, this modality is primarily sensitive to abnormalities of the bony cortex and considerably less sensitive to marrow abnormality. MR imaging was performed using a superconducting magnet operating at a field strength of 1.5 T. Sagittal images were obtained through the sternum and spine using a slice width of 5 mm, and corona' images were obtained through the lower lumbar spine, sacrum, pelvis, and proximal portion of the femur using a slice width of 8 mm. In 7 patients (47%) focal or diffuse abnormalities were detected by MR. In all patients the lesion were hypointense on Ti-weighted images (500/15), and the same lesions were demonstrated poorly on T2-weighted images (2000/90). In 4 cases with MR abnormality, low intensity lesions on T1-weighted images were enhanced by injection of gadolinium DTPA. MR imaging should be performed routinely in the staging of small cell lung cancer prior to bone marrow biopsy for the complete evaluation of bone marrow status.