Proton MR spectroscopy of squamous cell carcinoma of the upper aerodigestive tract: in vitro characteristics.

PURPOSE To determine the ability of in vitro high-field-strength proton MR spectroscopy to differentiate squamous cell carcinoma of the upper aerodigestive tract from uninvolved muscle. METHODS Surgical specimens of squamous cell carcinoma arising from the upper aerodigestive tract (n = 18) and from muscle (n = 13) were examined in vitro using high-field (11 T) proton MR spectroscopy. The peak heights of choline and creatine were measured for tumor and muscle at echo times of 136 and 272. The choline/creatine (Cho/Cr) ratio was compared between tumor and normal tissue for each echo time. Student's t test was used to determine whether a significant difference existed between proton MR spectroscopic measurements of the Cho/Cr ratio for tumor and muscle. RESULTS The mean Cho/Cr ratio was consistently higher in tumor than in muscle at all echo times; however, statistically significant differences between tumor and muscle were identified only at longer echo times (136 and 272). CONCLUSION The Cho/Cr peak height ratio can be used to differentiate tumor from muscle in vitro (at 11 T).