Volume‐localized two‐dimensional correlated magnetic resonance spectroscopy of human breast cancer

Abstract

A localized 2D correlation spectroscopic sequence (L-COSY) was implemented and applied in human breast cancer in vivo to evaluate the water to fat (both saturated and unsaturated) ratios and also to identify choline. Being in agreement with the conventional 1D magnetic resonance spectroscopy (MRS) results, elevated water to lipids ratios were found in breast cancers and choline was observed only in a few cancer patients. J. Index terms: 1 H MR spectroscopy; saturated fatty acid; unsaturated fatty acids; water; choline DIAGNOSIS AND TREATMENT of the breast tumor, the second most common cancer among women, remain a significant medical challenge. The high priorities of breast cancer are early detection, diagnosis, and timely treatment. The clinical needs with respect to lesion characterization and staging have not been well addressed by mammography and other conventional imaging and diagnostic tools.Proton magnetic resonance spectroscopy ( 1 H MRS) of surgically excised breast tumors was first performed by Chu et al. with differences between the malignant and uninvolved healthy tissues reported, but malignant and benign tissues were indistinguishable with 1 H MRS (1). Kaplan and Cohen investigated 1 H MRS of breast cancer cells; peaks due to various choline groups (Cho), creatine/phosphocreatine (Cr/PCr), and lactate (Lac) were reported (2). MRS of 108 plasma samples from patients with breast tumors and from healthy subjects showed significant line width changes in methylene peaks (3). The water to fat ratios were calculated in patients with malignancy and benign tumors, and the ratios were high in the affected side, compared to the unaffected side (4 -6). Cho levels have been recently investigated in breast carcinomas and unaffected breasts (5-7). Mackinnon et al. used 1 H MRS ex vivo to differentiate the fine-needle biopsy specimens of benign breast lesions from invasive cancer (8).A major concern with 1D MRS is that the spectral peaks severely overlap each other. In particular, the dominant peaks due to lipids in the breast overlap with those of metabolites. Spectral editing and multiple quantum (MQ) techniques can be used to differentiate lactate and other metabolites from the overlapping lipids (9 -12). A drawback of the spectral editing technique is that only one metabolite can be selectively detected (9,10). Reduced signal strength of metabolites is a primary concern with MQ techniques (11,12). Several versions of localized 2D MRS have been successfully implemented on a whole-body 1.5T MR imaging (MRI) scanner (13-17). Due to an added dimension, a localized 2D MR spectrum has a better resolution than a conventional 1D MR spectrum (13-18). The objectives of this work were threefold: 1) to implement and evaluate a localized 2D correlated MR spectroscopic sequence (L-COSY) in the human breast and to quantitate the levels of lipids (saturated and unsaturated), water, and metabolites using a dedicated phased-array breast coil; 2) to investigate the regional variations of lipids, metabolites, and water using the 2...

Monitoring the therapeutic response of locally advanced breast cancer patients: Sequential in vivo proton MR spectroscopy study

“…It has been reported that mice tumors contain 84% water by tissue weight, whereas fat accounts for only 12% (37). It was recently reported that the reduction in fat signal is most probably due to the loss of mammary fat tissue in breast cancer (38). This may be one reason for the reduced lipid signal observed in most breast cancer patients in our study.…”

Localized two‐dimensional 1H magnetic resonance exchange spectroscopy: A preliminary evaluation in human muscle

“…The presence of ZQC during TM leads to 2D ZQ-filtered COSY cross peaks (12,18). The ZQ-filtered COSY cross peaks of an oil phantom look similar to a COSY spectrum of a healthy human breast in vivo showing the J-connectivities between the protons of unsaturated and saturated lipids (26). Two pairs of cross peaks were identified at the following locations: C1 (F 2 ϭ 5.4 ppm, F 1 ϭ 2.9 ppm), C2 (F 2 ϭ 5.4 ppm, F 1 ϭ 2.2 ppm), C1Ј (F 2 ϭ 2.9 ppm, F 1 ϭ 5.4 ppm), and C2Ј (F 2 ϭ 2.2 ppm, F 1 ϭ 5.4 ppm).…”

GAVA: Spectral simulation for in vivo MRS applications

“…For in vivo measurements, MR spectroscopic data is complicated by the inherent overlap and complex shapes of the signals of interest. Methods to improve detection of specific spectral contributions include spectral editing [4,18,28,33,[46][47][48]; spectral fitting using constrained parametric model optimization and incorporating a priori metabolic information [6,7,23,24,31,35,40,45,50]; and use of multidimensional spectral acquisition methods [42][43][44]. In all of these areas of research, spectral simulation methods are becoming an increasingly important tool.…”