Metabolic characterization of primary and metastatic ovarian cancer by ¹H‐MRS in vivo at 3T

Abstract

1 H-MRS was performed on 12 women (age range 45-72) with ovarian cancer of FIGO stage 3 or above using a 3T MRI system with an 8-channel cardiac receive coil. Respiratory-triggered PRESS-localized spectra (TE ‫؍‬ 144 ms) were obtained separately from an ovarian mass and from metastatic disease. Peak areas were quantified relative to unsuppressed water using LCModel and spectra were discarded if LCModel reported signal-to-noise ratio (SNR) < 3 or if no metabolites were reported with standard deviation (SD) < 30%. The cystic fraction of each voxel was estimated by thresholding T 2 -weighted images, and this was used both to correct the reported metabolite concentrations and to calculate an expected SNR of choline using the measured SNR of water. Choline was detected in 10/12 primary tumors and 5/11 metastatic lesions (range 2.0 -16.6 mM). Of the 8/23 failures, 7 had a predicted choline SNR < 2, confirming that the failure to detect choline could be explained by technical problems. Glycine was observed in one benign lesion. 1 H-MRS can be used to quantify choline in primary and metastatic masses in ovarian cancer, but the moderately high rate of failure to detect choline necessitates careful recording of data quality parameters to discriminate true from false negatives. Magn Reson Med 62:855-861, 2009.

In vivo magnetic resonance spectroscopy for ovarian cancer diagnostics: quantification by the fast Padé transform

“…The main metabolite peaks resolved were: lipid (Lip) at 1.3 ppm (parts per million), an inverted lactate (Lac) doublet also at around 1.3 ppm, creatine (Cr) at 3.0 ppm, choline (Cho) at 3.2 ppm or total Cho between 3.14 and 3.34 ppm and Lip at 5.2 ppm. In addition, a peak with resonance frequency between 2.0 and 2.1 ppm was reported by some authors [48][49][50][51][52]54]. Based upon in vitro analysis, this peak was found to be comprised of N-acetyl aspartate (NAA) as well as N-acetyl groups from glycoproteins and/or glycolipids [50].…”

“…Several investigative teams have applied in vivo MRS with the aim of improving ovarian cancer diagnostics. We performed a systematic search 3 of the literature and found published results for 134 malignant ovarian lesions, 114 benign ovarian lesions and 3 lesions of the ovary that were classified as "borderline" (BL), using in vivo proton MRS time signals encoded via clinical (1.5 or 3 T) magnetic resonance (MR) scanners [40,[43][44][45][46][47][48][49][50][51][52][53][54][55]. Appendix 1 provides a summary of the clinical aspects and design of these studies, with salient information concerning the reported MRS data.…”

“…In most of the studies, some assessment of spectral quality, notably, Signal-noise ratio (SNR) was reported, with these issues addressed in detail in Ref. [52]. The common methodologic feature of all these in vivo studies was that the MRS time signals were processed by the fast Fourier transform (FFT) as is the conventional practice, with eventual post-processing via fitting in some instances, such as in Refs.…”

“…The common methodologic feature of all these in vivo studies was that the MRS time signals were processed by the fast Fourier transform (FFT) as is the conventional practice, with eventual post-processing via fitting in some instances, such as in Refs. [40,45,51,52,54].…”

Role of Imaging in Peritoneal Surface Malignancies

“…[26] This modality uses the principle of evaluating choline metabolites. Further advances in MRI technology may help in evaluating the technique further.…”