Ahmed Abdel Razek, Presenter: Nothing to Disclose

Ahmed Motamed, Abstract Co-Author: Nothing to Disclose

Nadia Nada, Abstract Co-Author: Nothing to Disclose

Sieza Samir, Abstract Co-Author: Nothing to Disclose

Nermain Soliman, Abstract Co-Author: Nothing to Disclose

To predict parotid malignancy using diffusion weighted MR imaging and proton MR spectroscopy (MRS).

This study included 48 patients (28M, 19F aged 18-72 ys: mean 47ys) with parotid mass. They underwent routine MR imaging, diffusion weighted MR imaging and MR spectroscopy on 1.5 tesla MR unit. Diffusion weighted MR imaging was done using echo planar imaging with calculation of apparent diffusion coefficient (ADC) value. Single voxel proton MR spectroscopy was performed. The acquisition parameters were: TR= 3000msec, TE=135 msec, 16X16 phase encoding matrix, 1250 Hz spectral width & 2 averages. Integral of assigned metabolites calculated. Mean ADC value and metabolite peaks correlated with histopathological results.

The mean ADC value of the malignant parotid tumor was 0.91±0.11X10-3 mm2/sec and of benign lesions was 1.44±0.19 X10-3 mm2/sec. The mean choline/creatine (Ch/Cr) ratio was 3.9 in malignant tumors and 2.5 in benign tumors. There was statistically difference in ADC value (P<0.001) and Ch/Cr ratio (P<0.04) between benign lesions and malignant parotid tumors. The Ch/Cr ratio correlated well with the ADC value (r=0.85). Selection of 1.21X10-3 mm2/sec for ADC value of 2.6 for Ch/Cr ratio as the thresholds to predict malignancy in parotid mass has sensitivity of 100% and 91%, specificity of 94% and 88% and accuracy of 96% and 89% respectively.

We concluded that apparent diffusion coefficient value and choline/creatine ratio is new non invasive quantitative parameters used for prediction of parotid malignancy.

Diffusion weighted MR imaging and proton MR spectroscopy of the parotid gland increased diagnostic performance of MR imaging for prediction of parotid malignancy.

Abdel Razek, A, Motamed, A, Nada, N, Samir, S, Soliman, N, Prediction of Malignancy in Parotid Mass: Diffusion-weighted Echoplanar MR Imaging and Proton MR Spectroscopy.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5000226.html