Dynamic enhanced MRI of tongue carcinoma

Dynamic enhanced magnetic resonance imaging (MRI) of healthy tongues (20 cases) and tongue squamous cell carcinomas (44 cases) was carried out to investigate time-dependent enhancement patterns in these tissues. In addition, correlations between dynamic enhanced MRI and clinical features were analyzed. T1-weighted spin echo sequence (TR/TE/excitations=200/20/1) coronal plane images were obtained with a 1.5-Tesla superconducting MRI imager. Both qualitative and quantitative analyses were performed. For quantitative analysis, signal intensity of the operator-defined region of interest (ROI) was measured and the signal enhancement to noise ratio (SE/N) was calculated. In addition, time versus SE/N was plotted (signal-intensity [SI] ratio curve) and then classified into 1 of 5 patterns (long or short time to peak enhancement, rapid or gradual wash-out, and no enhancement). The results were as follows: In normal tongues, the lingual mucosa and high signal and low signal regions of the tongue musculature corresponding to the intrinsic tongue muscles were differentiated on all images. Intrinsic tongue muscles showed a long time to peak enhancement and gradual wash-out patterns. Of the 44 cases of tongue carcinoma, 40 (90.9%) were detectable on dynamic enhanced images. The 4 tumors that could not be detected on dynamic enhanced MRI were T1-stage tumors and showed superficial growth patterns. The tongue carcinomas enhanced rapidly in comparison to the musculature of normal tongues. The enhancement patterns correlated well with tumor size and clinical features. That is, small tumors showed a homogenous enhancement pattern and large tumors showed a marginal enhacement pattern (p<0.01). Further, endophytic and exophytic tumors tended to show a peripheral enhancement pattern, whereas superficial tumors tended to show a homogenous enhancement pattern (p<0.05). No significant correlations were found between enhancement timing and clinical features. In cases showing a peripheral enhancement pattern, the central region tended to become gradually enhanced in comparison to the peripheral region. Maximum SE/N tended to increase with tumor size. In contrast, the time of maximum SE/N and %-wash out tended to decrease with tumor size, and endophytic growth-pattern tumors tended to show a low %-wash out value. The features of dynamic enhanced MRI appear to correlate well with tumor size and growth patterns in cases of tongue carcinoma. (author)