Abstract:
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Purpose: Diffusion-weighted MR imaging with Single Shot Fast Spin Echo Sequence (DW-SSFSE) is expected to improve conspicuousness of lesions because of its lower susceptibility effect. The purpose of this study was to evaluate the efficacy of DW-SSFSE in differentiating between benign and malignant mass lesions of the head and neck .
Methods and Materials: Fourty-four mass lesions of the head and neck were examined in fourty-four patients (24 men and 20 women, mean 53 years old). The diffusion-weighted imaging with single shot fast spin echo sequence (DW-SSFSE) was implemented on a 1.5T Signa Horizon LX MRI system (GE Medical Systems, Milwaukee, WI, U.S.A.). Four images in axial or coronal plane were acquired with diffusion sensitization along the three directions with b=1000s/mm 2 following an acquisition with b=0. Apparent diffusion coefficients (ADCs) were calculated in regions of interest (ROI) from DW-SSFSE images. ADC maps (x, y, z) were constructed by calculating the ADC using the Stejskal-Tanner formula on a pixel-by-pixel basis. Averaging of the three diffusion-weighted images at each b value has also been made to obtain isotropic diffusion-weighted images. In six patients, a syringe of distilled water was simultaneously scanned and the ADCs were calculated as a reference.
Results: In 44 patients, the ROI could be set and the ADC could be calculated. The ADC value (0.67+-0.12 mm2/sec; mean+-SD) of malignant lymphoma (n=4) were lower than those (1.12+-0.24) of the other malignant lesions (n=16). The ADC values (1.69+-0.53) of the benign lesions (n=24) were significantly (p<0.05) higher than those of the malignant lesions. When an ADC smaller than 1.50 x 10-3mm2/sec was used for predicting malignancy, accuracy of 80% (35/44), with 95% (19/20) sensitivity (30/39) and 67% (16/24) specificity, was obtained.The ADC values (2.39+-0.19) of distilled water were almost same as the known values.
Conclusion: Although the number of patients in our preliminary study is limited, diffusion-weighted MR imaging with SSFSE is reliable for ADC measurement of benign and malignant mass lesions of the head and neck and may be a useful technique in differentiating between them.
Adachi MD, Y,
Diffusion-weighted MR Imaging of the Head and Neck Lesions with Single Shot Fast Spin Echo (SSFSE) Sequence. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3107606.html
