RESUMO
AIM: To evaluate the feasibility of performing in vivo proton magnetic resonance spectroscopy ((1)H-MRS) of cervical lymph nodes, and the clinical usefulness of the technique in the characterization of cervical lymphadenopathy. MATERIALS AND METHODS: Cervical lymphadenopathy was examined in 20 individuals with malignant disease, i.e. 10 with squamous cell carcinoma (SCC), 6 with undifferentiated carcinoma (UDC) and 4 with non-Hodgkin's lymphoma (NHL). Cervical lymphadenopathy was also examined in 4 individuals with benign disease, i.e. 3 with tuberculosis (TB) and 1 with Castleman's disease. A point-resolved spectroscopic sequence with echo times (TE) of 136 and 272 ms and a time-domain spectral fitting procedure were used to estimate peak amplitude of choline (Cho), creatine (Cr) and unsuppressed water. Cho/Cr and Cho/water ratios were measured for each lesion. The mean ratio for each lesion group was obtained and results were compared statistically. RESULTS: At TE of 136 ms, spectra were interpretable in all 24 cases and a Cr peak was identified with post-processing in 15 cases. The Cho/Cr and Cho/water ratios for NHL were 9.1 +/- 5.2 and 1.7 +/- 0.2 x 10(-3), for UDC were 4.4 +/- 0.9 and 1.2 +/- 0.4 x 10(-3), and for SCC were 2.1 +/- 0.6 and 0.5 +/- 0.3 x 10(-3), respectively. Both Cho/Cr and Cho/water ratios for UDC were significantly higher than SCC (p = 0.002 and 0.026, respectively). At TE of 272 ms, spectra were interpretable in 22 of 24 cases and a Cr peak was identified with post-processing in 11 cases. Cho/Cr and Cho/water ratios for NHL were 5.4 and 4.6 +/- 1.4 x 10(-3), for UDC were 4.2 +/- 1.5 and 2.6 +/- 1.0 x 10(-3) and for SCC were 2.5 +/- 1.1 and 1.3 +/- 0.6 x 10(-3), respectively. The Cho/water ratio for UDC was significantly higher than for SCC (p = 0.04). The Cho/Cr ratio for UDC was also higher than for SCC, but this difference was not statistically significant (p = 0.07). Neither Cho nor Cr was detected in the 3 cases of TB. CONCLUSION: In vivo (1)H-MRS is a feasible technique for the evaluation of cervical lymph nodes and it offers potential as a clinical tool in the investigation of cervical lymphadenopathy. However, further studies with larger patient cohorts are needed to validate the findings of this initial report.