الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The current study is a prospective case series study which tries to evaluate the accuracy of three common imaging modalities which are CT, MRI and US. The study focused on these three modalities because they are the most widely available, highly prescribed and affordable imaging techniques.
The current study included 110 patients recruited from the outpatient clinics of Otorhinolaryngology, General surgery and Oncology departments. The study patients included 62 males and 48 females with age range from 8 to 77 years old.
Those 110 patients were distributed between 7 anatomical regions: nasopharynx (15 patients), oropharynx (9 patients), hypopharynx (16 patients), larynx (17 patients), thyroid (21 patients), lymph nodes (19 patients) and salivary glands (13 patients). The final pathological diagnosis revealed 67 cases with malignant tumors and 23 cases with benign neoplasia and 20 cases with inflammatory lesions.
Our study has not involved ordering US, CT and MRI for every patient because this has not been applicable being depending on the decision of the treating physician. Accordingly, the study included 99 CT, 73 MRI and 53 US reports. Seventy three (73) patients with neck lesion were subjected to both MRI and CT. While 42 patients with lesions of thyroid, lymph nodes or salivary glands were subjected to both CT and US. Finally, 32 patients with lesions of thyroid, lymph nodes or salivary glands were subjected to both MRI and US.
The results of imaging were assessed based on the corresponding histopathological diagnosis to define the true benign, true malignant, false benign and false malignant results each imaging modality.
Summary
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The number of these cases was used to calculate sensitivity, specificity, diagnostic accuracy, Precision (positive predictive value) and negative predictive value along with comparison between the three imaging modalities.
We found that, ultrasound, computed tomography and magnetic resonance imaging, all are effective imaging modalities for evaluating a neck mass. Overall sensitivity of US, CT and MRI were 87.1%, 80.6% and 88.2% respectively. Overall specificity of US, CT and MRI were 81.8%, 73% and 81.8% respectively. Overall accuracy of US, CT and MRI were 84.9%, 77.8% and 86.3% respectively.
Every anatomical region in the neck has its own criteria making it the target of specific imaging modality. So ultrasound is the preferred imaging technique for thyroid While CT and MRI are the preferred imaging techniques for larynx and pharynx.
MRI is significantly better than CT in diagnosing neck lesions ,while US is significantly better than CT in diagnosing lesions of thyroid, lymph nodes and salivary glands.