الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
A thyroid nodule is a lump that can develop in thyroid gland. It can be solid or filled with fluid .Patient can have a single nodule or a cluster of nodule. It can be benign or malignant. If the nodule gets large enough , patient may develop many symptoms such as pain at the base of neck , swallowing difficulties , hoarseness of voice.
There are different imaging modalities are used of thyroid nodules, they in diagnosis include thyroid ultrasound ,CT neck ,MRI diffusion ,Fine needle aspiration , to collect a sample of the nodule for testing in a laboratory (Histo-pathological ).
The aim of our study is to evaluate the diagnostic value of the MRI diffusion in differentiation between benign and malignant thyroid nodule confirmed by fine needle aspiration.
All patient included in the study underwent thyroid ultrasound , MRI DWI of neck and FNAC.
US and color Doppler ultrasonography are useful for evaluation of thyroid nodules, but there is no single US criterion that can reliably distinguish benign from malignant thyroid nodules. So, TIRADS classification is needed to assess the possibility of presence of malignancy of thyroid nodules.
The present study showed that DWI with ADC value is highly valuable, noninvasive in differentiation between benign and malignant thyroid nodules. Malignant thyroid nodules have low ADC value but benign nodules have high ADC values.
The main goal of thyroid FNAC is the early differentiation between non-malignant and malignant nodules. Use of ultrasonography in FNAB increases significantly the sensitivity, specificity and accuracy of the results of FNAC and help to localize which area will be aspirated at the thyroid nodules.
Conclusion
There were low ADC values of malignant nodules. Benign nodules, however had higher values of ADC than malignant nodules. Measurement of
DWI and ADC include objective evaluation of the lesions. DWI also has the benefit of being a rapid sequence that is noninvasive and does not require a contrast agent.
DWI may be helpful in differentiating malign and benign thyroid nodules. The cutoff values derived from our study may be used as threshold values in larger prospective trials for the necessity of FNAB for the individual patient.