Proton magnetic resonance spectroscopy used with MRI can be very effective at diagnosing suspicious breast lesions, generating fewer false positives and reducing the need for painful and anxiety-inducing biopsies, finds a new study.

It is a non-invasive technique that can be used to measure the concentrations of different chemical components within tissues and can provide a detailed look at the physiology of an image generated by an MRI.

According to the study, the proton spectroscopy detects cancers based on elevated levels of choline compounds — the marker of an active tumour.

The study, conducted at Memorial Sloan-Kettering Cancer Center in New York, appears in the October issue of the journal Radiology.

MRI has been shown in previous studies to be highly effective in identifying breast masses that other forms of screening, such as mammogram or ultrasound, may have missed or flagged as suspicious.

However, it is not 100 per cent accurate and can lead to false positives, requiring a biopsy, say the authors.

"Biopsy is often necessary to distinguish benign enhancing non-mass lesions from cancer," reads the study.

Non-mass enhancing lesions are areas of breast tissue that are not a mass or lump and may extend over large or small regions. Non-mass lesions occur with benign hormonal changes, but can also signify malignancy.

In the study, 32 women with a median age of 49 with non-mass benign and malignant lesions were screened with proton MR spectroscopy. The test revealed that 15 of the 32 lesions were positive for elevated choline, including all 12 cancers and three of 20 benign lesions.

Those findings indicate that proton MR spectroscopy has a 100 per cent rate of detecting cancer and an 85 per cent rate of detecting malignant non-mass lesions, says the study.

If biopsies of only the lesions with elevated choline had been conducted, based on the results of the proton MR spectroscopy test, biopsies would have been avoided for 17 of the 25 lesions (68 per cent), say the authors. And no cancer would have been missed.

"Non-mass enhancing lesions frequently pose a dilemma to the radiologist when evaluating the breast for the presence of cancer, especially in pre-menopausal women," said the study's lead author, Lia Bartella, director of breast imaging at Eastside Diagnostic Imaging in New York.

"Potentially, the use of proton MR spectroscopy may help decrease the number of benign biopsies for non-mass enhancing lesions."