الفهرس 
Introduction.Only 14 pages are availabe for public view
 |  | from | 164 |  |  |
| | | from | 164 | | |
Abstract
Upper extremity entrapment and compression neuropathies are traditionally diagnosed on the basis of clinical history and the results of physical examination and electrophysiologic studies Although electrophysiologic studies are mildly invasive and operator dependent, the location and severity of the underlying nerve injury can usually be determined.
Limitations include inabilities to determine structural causes of denervation or to assess spatial information. MR imaging may provide useful information with regard to the exact anatomic location of the lesion or may aid in narrowing the differential diagnosis. In patients with peripheral neuropathy, MR imaging may establish the origins of the condition and provide information crucial for management or surgical planning.
The aim of this study is to assess the accuracy of magnetic resonance imaging in the diagnosis of peripheral neuropathies of the Median, Radial, and Ulnar Nerves, using surgery & clinical data as a reference gold standard.
This is a descriptive study conducted upon patients had suspected peripheral neuropathies of median, radial & ulnar nerves. This study included 30 cases (15 right side and 15 left side). The study consisted of 10 women (33.3 %) and 20 men (66.7%) was done in the Radiology & Imaging department Suez Canal University Hospital in Ismailia starting from June 2010 till March 2013.
Our study included all patients aged 18 to 70 years who referred from outpatient clinic with suspected peripheral neuropathies of median, radial & ulnar nerves with the following exclusion criteria: Cognitive disorder (e.g., mental retardation, dementia). Cardiac pacemakers, older aneurysm clips, new stents or aortic valves, ferromagnetic ocular fragments that could interfere with high-strength magnetic fields.
The diagnosis is suspected clinically when patient had experience of chronic forearm & hand pain. Experience paresthesia and numbness of the affected hand, weakness and atrophy due to prolonged nerve compression. Also if patient had history of nerve Injuries, Infections (viral or bacterial), and mass lesions.
The role of imaging is to identify the exact anatomic site of examined nerve & the site of lesion. It also detected the size, shape, signal intensity and degree of compression of examined nerve. It detected the cause of neuropathy either entrapment or non entrapment. It detected abnormality causing the entrapment, such as neoplasm, arthritis and congenital anomaly. Secondary signs of nerve entrapment include the effects of the entrapment on the nerve itself, such as focal flattening, proximal swelling, or neural signal hyperintensity on MRI, and abnormalities of the muscles supplied by the affected nerve, such as acute denervation edema or chronic fatty atrophy.
In our study we found the accuracy of MRI in diagnosis of peripheral neuropathy in comparison with clinical and surgical assessment was 96.6 %. with sensitivity (93.1%) and specificity (100%).
Sensitivity and specificity test for MRI in diagnosis of median neuropathy illustrates probability of being true positive is (97.2%) more than being false positive when repeat test 100 times with sensitivity (94.4%) and specificity (100%).
Sensitivity and specificity test for MRI in diagnosis of radial neuropathy illustrates probability of being true positive is (75%) more than being false positive when repeat test 100 times with sensitivity (50%) and specificity (100%).
Sensitivity and specificity test for MRI in diagnosis of ulnar neuropathy illustrates probability of being true positive is (95.2%) more than being false positive when repeat test 100 times with sensitivity (100%) and specificity (90.5%).
Sensitivity and specificity test for MRI in diagnosis of nerve entrapment illustrates probability of being true positive is (96.9%) more than being false positive when repeat test 100 times with sensitivity (91.6%) and specificity (93.7%). Sensitivity and specificity test for MRI in diagnosis of non-entrapment neuropathies illustrates probability of being true positive is (96.6%) more than being false positive when repeat test 100 times with sensitivity (94.1%) and specificity (93.1%).
We found that peripheral nerve dimensions at the site of lesion are ranging from 3 to 20 mm. In all cases return to normal girth was seen distal & proximal to the site of abnormality as its dimensions proximally were ranging from 3 to 7 mm and distally were ranging from 3 to 8 mm.
In our study nerve shape was oval in twenty two (73.3%) patients & was flat in 8 patients. Six subjects (20%) showed normal nerve size also six subjects (20%) had small nerve size. Eighteen subjects (60 %) had enlarged size.
Also we found that thirteen subjects (43.3%) had low signal intensity in T1 & high signal intensity in T2 . Six subjects (20%) had high signal intensity on T1 and low signal intensity on T2. Two subjects (6.7%) had high signal intensity on T1 and high signal intensity on T2. Five subjects (16.7 %) had low signal intensity in T1 and low signal intensity on T2. Four subjects (13.3%) had high signal intensity in T1 & high signal intensity in STIR. Sixteen subjects (50 %) had normal muscle volume, however fourteen (50 %) subjects had decreased muscle volume. Five subjects (16.7%) had muscle edema, however, Fifteen subjects (50%) had muscle atrophy.