A series of patients with clinically early inflammatory joint disease due to rheumatoid arthritis, psoriatic arthritis and Reiter's syndrome were examined by plain film radiography and magnetic resonance imaging (MRI). The spin echo T1-weighted precontrast, T2-weighted, and, especially, T1-weighted postcontrast images demonstrated distinct differences in the distribution of inflammatory changes, both within and adjacent to involved small hand joints. Two major subtypes of inflammatory arthritis were shown, thus providing a specific differential diagnosis between rheumatoid arthritis and some patients with seronegative spondyloarthritis. In particular, all the patients with Reiter's syndrome who were studied, and half of those with psoriatic arthritis, had a distinctive pattern of extra-articular disease involvement. The need for a new classification of clinical subsets in psoriatic arthritis has been recently suggested. The present findings suggest that magnetic resonance imaging could be useful in such a reclassification of seronegative spondyloarthritis, as well as offering considerable potential for a reappraisal of pathogenesis and therapy. In this series, it was also noted that juxta-articular osteoporosis on plain film did not correlate with bone marrow oedema on MRI. Hence the aetiology of this common radiographic finding also merits further consideration.

Vertebral infection represents 2-4% of all cases of osteomyelitis. An increase in the incidence of pyogenic as well as granulomatous spondylitis has been noticed. Early radiological diagnosis is of great importance for prompt treatment and prevention of clinically significant consequences which include neural compromise and late spinal deformities. The most frequent causative pyogenic micro-organisms are gram-negative bacteria especially Staphylococcus aureus. An important form of nonpyogenic granulomatous infection is tuberculous spondylitis which represents the most common form of extrapulmonary tuberculosis. The routes of spinal infection include hematogenous spread, postoperative infections, direct implantation during spinal punctures and spread from a contiguous focus. The role of imaging is an early diagnosis, evaluation of extent of infection with special regard to potential neural compromise, differential diagnosis, guidance of diagnostic biopsy, planning of eventual operative procedures and assessment of therapeutic response. Imaging modalities include bone scintigraphy, radiography, CT and MRI. In practice, usually a combination of a sensitive and a specific method is utilised. The only imaging modality which combines high sensitivity with satisfactory specificity is MRI. This is the reason that MRI frequently has become the first imaging modality in clinically suspect spinal infection. The MRI is the method of choice for direct demonstration of extension of infection, especially of eventual epidural abscess or phlegmon and consecutive neural compression. Using MRI monitoring of therapeutic efficiency is possible.

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Purpose: To evaluate effect of platelet-rich plasma gel (PRPG), locally administered during the anterior cruciate ligament (ACL) reconstruction, with two MRI methods. The proximal tibial tunnel was assessed with diffusion weighted imaging (DWI) and with dynamic contrastenhanced imaging (DCE-MRI). Materials and Methods:In 50 patients, standard arthroscopic ACL reconstructions were performed. The patients in the PRPG group (n ¼ 25) received a local application of PRPG. The proximal tibial tunnel was examined by DWI and DCE-MRI, which were used to calculate apparent diffusion coefficient (ADC) values, as well as the contrast enhancement gradient (G enh ) and enhancement factor (F enh ) values.Results: At 1 month, the calculated average ADC value in the PRPG group was significantly lower than in the control group. At 2.5 and at 6 months, G enh was significantly higher in the PRPG group. There were no significant differences in F enh between the groups at any control examination.Conclusion: DWI and DCE-MRI measurements indicate a reduced extent of edema during the first postoperative month as well as an increased vascular density and microvessel permeability in the proximal tibial tunnel at 1 and 2.5 postoperative months as the effect of the application of PRPG.