Classification of human tumours by high-resolution magnetic resonance spectroscopy.

Malignant tumours yield a high-resolution proton magnetic resonance (MR) spectrum. Fifty-one tumour biopsy specimens from patients with cancer of the ovary or colon were examined by magnetic resonance spectroscopy (MRS) to determine whether it was possible to identify tumour subtypes with metastatic potential. Relaxation parameters (T2) for visible lipid methylene protons were within the range of those measured for three animal metastasis models. Primary carcinomas with metastases gave T2 values greater than 350 ms, whereas carcinomas not associated with known metastases at the time of tumour excision gave a range of values from 150 to 1500 ms. All but two carcinomas gave a long T2 (greater than 350 ms) indicating metastatic potential. The MRS method designated five of six histologically borderline epithelial ovarian tumours as malignant with metastatic potential. MRS may be sensitive enough to detect malignant cells in a tumour which is of intermediate or borderline malignancy by light microscopy. Malignancy without a potential for metastasis is uncommon.