Proton and Phosphorous MR Spectroscopy in Squamous Cell Carcinomas of the Head and Neck

Rationale and Objectives: Phosphorous magnetic resonance spectroscopy (³¹P MRS) has been used to evaluate and predict treatment response in squamous cell carcinoma of the head and neck (HNSCC). Several studies have also shown the potential of proton MRS (¹H MRS) in assessing response in HNSCC. In view of the inherent limitations associated with performing ³¹P MRS in clinical settings, the current study was performed to explore whether ¹H MRS could provide similar or complementary metabolic information in HNSCC. Materials and Methods: Fifteen patients with HNSCC underwent pretreatment magnetic resonance imaging. Both ¹H MRS and ³¹P MRS were performed on viable solid parts of the metastatic lymph nodes of these patients. Peak areas of total choline (tCho) and unsuppressed water as observed on ¹H MRS and phosphomonoester (PME) and β-nucleotide triphosphate (β-NTP) on ³¹P MRS were computed. Pearson's correlation coefficient was used to correlate the tCho/water and PME/β-NTP ratios. Results: In all patients, the metastatic nodes appeared hyperintense on T2-weighted images and hypointense on T1-weighted images with variable signal intensity. A prominent resonance of tCho on ¹H MRS and a resonance of PME on ³¹P MRS from the metastatic nodes of all patients were observed. A moderate correlation of 0.31 was observed between tCho/water and PME/β-NTP (P > .05). Conclusions: The biochemical pathways involved in ¹H MRS of tCho may be different from the phospholipid metabolites seen on ³¹P MRS of head and neck cancers, and thus the two MRS techniques may be complementary to each other.