الفهرس 
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Abstract
Carpal tunnel syndrome (CTS) is the commonest one of upper limb compression neuropathies. It represents about 90% of all entrapment neuropathies. CTS is caused by entrapment of the median nerve while passing in the carpal tunnel at the level of the wrist. CTS is widely distributed as an occupational health condition; especially in workers who are exposed to activities that include high force/pressure or the use of repetitive vibrating appliances. CTS has an unclear, multifactorial etiology. A variety of causative factors can affect the median nerve in the carpal tunnel. Certain clinical examinations have been used as components of a clinical diagnosis of CTS; however, their accuracy has been a matter of debate. The traditional symptoms of CTS include pain, numbness, and tingling in the areas supplied by the median nerve, but numbness may be extended to affect all the fingers. Symptoms usually worsen at night and can arouse subjects from sleep. To decrease the intensity of symptoms, patients usually “flick” their wrist as if shaking down a thermometer (flick sign). In cases with CTS, pain and parathesia may be extended to include forearm, elbow, and shoulder. In cases of severe CTS, there is usually atrophy of thenar muscles that finally lead to weak hand grip. Although electrodiagnostic tests (EDTs) are known to be proper diagnostic modalities for CTS, use of EDTs is considered an invasive method with a false-negative rate of nearly 20 % [4]. Since 1993, ultrasound evaluation has been one of the diagnostic methods for CTS patients. Ultrasound is considered a proper tool for CTS diagnosis that is readily obtainable, non-invasive maneuver, short time examination [6]. Until now, grey-scale ultrasound findings such as the median nerve crosssectional area at the level of the tunnel inlet and outlet were used for CTS diagnosis. Ultrasound elastography is a new imaging method introduced to assess tissue hardness. Sonoelastography is an ultrasound-based modality that can measure tissue elasticity. This method shows the relative strain of a structure compared with the surrounding tissue. The principle of elastography is based on light repeated pressure (compression and decompression) using a probe perpendicular to the lesion. The elastogram measures displacement of different tissues due to probe movement, calculated by a colour coded map. Stiff tissues exhibit less displacement in comparison with the surrounding connective tissue. Nowadays, it is widely used for differentiating between malignant and benign breast lesions and thyroid nodules, while its application in the musculoskeletal imaging field is limited. The aim of the study was to evaluate grey scale and elastography ultrasound imaging findings in patients with CTS in comparison with nerve conductive studies and clinical scores. This was a prospective cohort study that was performed on 30 patients with confirmed CTS according to clinical symptoms and nerve conductive study findings. All patients were subjected to full history taking and clinical examination, laboratory investigation, electrophysiological study, and imaging techniques. Summary of all results: • Regarding the disease characteristics in the study participants, of the total 60 wrists of the study participants, 25 (83.33%) patients had right affected wrist, 18 (60%) patients had left, and 17 (56.67%) patients had a normal wrist from both wrists. 17 (56.67%) patients had unilateral disease and 13 (43.33%) patients had bilateral. • Duration of symptoms ranged from 2 to 44 months with a mean value of 14.2 ± 13.71 months. • Regarding the severity of affected wrists, 9 (30%) wrists were mild, 20 (67%) were moderate, and 14 (47%) were severe. • Regarding the grey scale and elastography ultrasound outcomes in the study participants, CSA and strain ratio were significantly higher in CTS wrists than normal wrists (p <0.001). • Slightly reduced or decreased echogenicity relative to surrounding tissue were significantly higher in CTS wrists than normal wrists (p <0.001) also mobility were significantly higher in CTS wrists (p <0.001). • CAS was significantly lower in mild CTS wrists than moderate and severe CTS wrists (p =0.037, and 0.001 respectively) but there was no significant difference in CAS between moderate and severe CTS wrists. • Strain ratio was significantly lower in mild CTS writs than moderate and severe CTS wrists (p <0.001) and was significantly lower in moderate CTS wrists than severe CTS wrists (p <0.001). • CSA is a significant predictor of CTS (AUC: 0.882, p <0.001). At a cut off value of >11, it can predict CTS with a sensitivity of 74%, specificity of 88%, PPV of 94% and NPV of 58%. • Strain ratio is a significant predictor of CTS (AUC: 0.928, p <0.001). At a cut off value of >1.7, it can predict CTS with a sensitivity of 86%, specificity of 94%, PPV of 97% and NPV of 72%.