Preliminary study of proton magnetic resonance spectroscopy in bone and soft tissue tumors: an unassigned signal at 2.0-2.1 ppm may be a possible indicator of malignant neuroectodermal tumor

Abstract

Purpose: To evaluate the utility of proton magnetic resonance spectroscopy in bone and soft tissue tumors, especially whether or not the N-acetyl aspartate signal (NAA) could be recognized in neurogenic tumors.

Materials and methods: Forty-nine proton magnetic resonance spectroscopy studies were performed in 60 bone and soft tissue tumors. The patients were 28 males and 30 females. Eleven studies were incomplete, and were excluded from analysis. A point-resolved spectroscopy sequence (TR=1500 or 2000 ms, and TE=30, 60, 136, or 272 ms) was used on a 1.5-Tesla clinical MR scanner.

Results: An unassigned signal at about 2.0-2.1 ppm was recognized in six of 47 lesions: clear cell sarcoma (2/2), Ewing sarcoma (1/1), malignant fibrous histiocytoma (1/3), malignant schwannoma (1/1), and mucoepidermoid carcinoma (1/1). Neuroblastoma (1/1), primitive neuroectodermal tumor (1/1), and malignant melanoma (1/1) after chemotherapy or radiotherapy did not show this signal. This signal was not detected in neurofibroma (9/9), schwannoma (6/6), pheochromocytoma (2/2), or other mesenchymal tumors of non-neuroectodermal origin.

Conclusions: The assigned signal at about 2.0-2.1 ppm was detected in a small percentage of bone and soft tissue tumors and could be suggestive of an untreated malignant tumor of neuroectodermal origin.