Idiopathic inflammatory myopathy IIM (generally called Myositis) is a rare but serious condition characterised by the presence of skeletal muscle inflammation, causing muscle weakness and disability (Targoff 1998, Karpati and Hilton-Jones 2001, Harris-Love 2003, Sultan et al 2002, Plotz 1989). There is no 'Gold standard' test for diagnosing this disease which makes it challenging for physician. However, tests such as; muscle electromyogrphy (EMG), Creatine kinase serum (CPK) and biopsy are the best in current practice (Harris-Love 2003, Sultan et al 2002, Plotz 1989). All previous tests have their limitations. MR imaging has been successfully used to evaluate patients suspected of having IIM. MR images are reported following visual analysis by radiologists. In this research, two approaches were used to improve the diagnosis of Myositis with the aid of MRI: First: by using IDL PC software (In-house software developed to quantitatively analyse MR images and categorises its pixels according to their values). MR images and data were collected retrospectively. Second: by altering MR pulse sequences to achieve the optimum sequences for diagnosing myositis (data collected prospectively). Method: In this study, Quality Control tests were obtained and checked for all scanners used, Radiologists subjectivity in reporting MR images was tested and PC software reliability was assessed prior to commencing the main study to minimise error. Retrospective study: 43 patients were retrieved from the archiving system in a ITesla scanner and analysed using IDL PC software. The result was compared with other clinical tests such as biochemistry blood tests and biopsies. 68 patients were retrieved from the archiving system in a 1.5T scanner and analysed using IDL PC software. The results were also compared with other clinical tests. Prospective study: 15 patients were scanned with an 'optimised protocol' of MR pulse sequence. Contrast-to-Noise ratio (CNR) was to be measured, calculated and then compared with 'reference protocol' which was used as routine practice. Consequently, these two approaches were evaluated and compared with evidence of MRJ advantages in diagnosing myositis from the literature. Results: The study shows that IDL is consistent and gave reliable output readings in both available operating options (Manual- Automatic). Intra/ Inter observer reliability tests were (Manual .754, .998) (Automatic 1.0) The retrospective study suggested new techniques such as; PD with Fat.Sat which provide excellent tissue contrast for myositis patients. Conclusion: IDL software is a promising solution in computer-aid programmes. Using such programmes can minimise human error. In addition, new MR pulse sequence such (PD+FS) could be used for early diagnosis of myositis, as it provides helpful diagnosis information for Radiologists.