Imaging services at the Paralympic Games London 2012: analysis of demand and distribution of workload.

BACKGROUND: Very little data have been published on medical imaging services at disability games. 7.9 million euros (£6.6 million, US$11 million) were invested in setting up radiology facilities within purpose built polyclinics at the London 2012 Olympic and Paralympic games. This paper details imaging services at the 2012 Paralympic Games. Data analysis on imaging at 2012 Olympics has been published in a separate paper. AIM: To analyse the workload on the polyclinics' radiology services, provided for the Paralympic athletes during the London 2012 Paralympic Games. METHOD: Data were prospectively collected during the period of the Paralympic games from the Picture Archive Communications System (PACS) and the Radiological Information System (RIS). Data were correlated with the medical encounter database (ATOS). RESULTS: 655 imaging episodes were recorded, which comprised 38.8% (n=254) MRI, 33% (n=216) plain radiographs, 24% (n=157) ultrasound scans and 4.2% (n=28) CT scans. Investigations on the Paralympic athletes accounted for 65.2% of workload, with the remainder divided between Paralympic family and workforce. CONCLUSIONS: MRI was the most used imaging resource and CT was the least used imaging modality at the Paralympic village polyclinic. Analysis of demographic data provides a useful index for planning radiology infrastructure and manpower at future international competitions for athletes with a disability.

External impingement of the shoulder.

The relationship between external shoulder impingement and rotator cuff disease has been the subject of much research, but the theories of cause and effect remain controversial. Patients with symptoms of external impingement are referred for imaging to identify bony abnormalities of the coracoacromial arch and associated bursal and rotator cuff disease. Attempts have been made to identify objective imaging criteria that confirm the diagnosis of impingement, but at present external impingement remains primarily a clinical diagnosis. Therapeutic management varies from rehabilitation with physiotherapy to surgical procedures aimed at decompressing the subacromial space and repairing rotator cuff tears. This article reviews the relevant anatomy, biomechanics, and theories of external impingement, the role of imaging in the diagnosis of external impingement and rotator cuff disease, and implications upon management.

Radiological findings and healing patterns of incomplete stress fractures of the pars interarticularis.

OBJECTIVE: The objective was to retrospectively record the CT and MRI features and healing patterns of acute, incomplete stress fractures of the pars interarticularis. METHOD: The CT scans of 156 adolescents referred with suspected pars interarticularis stress fractures were reviewed. Patients with incomplete (grade 2) pars fractures were included in the study. Fractures were assessed on CT according to vertebral level, location of cortical involvement and direction of fracture propagation. MRI was also performed in 72 of the 156 cases. MRI images of incomplete fractures were assessed for the presence of marrow oedema and cortical integrity. Fracture healing patterns were characterised on follow-up CT imaging. RESULTS: Twenty-five incomplete fractures were identified in 23 patients on CT. All fractures involved the inferior or infero-medial cortex of the pars and propagated superiorly or superolaterally. Ninety-two percent of incomplete fractures demonstrated either complete or partial healing on follow-up imaging. Two (8%) cases progressed to complete fractures. Thirteen incomplete fractures in 11 patients confirmed on CT also had MRI, and 92% demonstrated oedema in the pars. Ten out of thirteen fractures (77%) showed a break in the infero-medial cortex with intact supero-lateral cortex, which correlated with the CT findings. MRI incorrectly graded one case as a complete (grade 3) fracture, and 2 cases as (grade 1) stress reaction. Six fractures had follow-up MRI, 67% showed partial or complete cortical healing, and the same number showed persistent marrow oedema. CONCLUSIONS: Incomplete fracture of the pars interarticularis represents a stage of the evolution of a complete stress fracture. The direction of fracture propagation is consistent, and complete healing can be achieved in most cases with appropriate clinical management. CT best demonstrates fracture size and extent, and is the most appropriate modality for follow-up. MRI is limited in its ability to fully depict the cortical integrity of incomplete fractures of the pars, but the presence of marrow oedema on fat-saturated T2-weighted sequences is a useful means of detecting acute spondylolysis.

Changes underlying the dynamic contrast-enhanced MRI response to treatment in rheumatoid arthritis.

OBJECTIVE: Dynamic contrast-enhanced MRI of patients with rheumatoid arthritis has shown a decrease in the early enhancement rate (EER) of synovitis after treatment. The purpose of this work was to investigate the underlying changes. METHODS: 3D dynamic contrast-enhanced images were acquired from 13 patients before and 1-2 weeks after anti-TNF alpha treatment. The EER of the inflamed synovium was measured. The T1 relaxation time of the synovitis was calculated from images at different flip angles. The time course of the arrival of gadolinium at the radial artery was determined. The gadolinium enhancement of the inflamed synovium was modeled to calculate the fractional plasma volume (vp), the fractional extravascular, extracellular fluid volume (ve), and the volume transfer constant (Ktrans). Pre- and post-treatment values were compared and the dependence of the EER on each parameter was assessed. RESULTS: There was a decrease in the EER measured over 26 s after treatment (29%, p = 0.002). Reductions in T1 (12%, p = 0.001), Ktrans (31%, p = 0.002), and vp (43%, p = 0.01) contributed to this; however, the EER was relatively insensitive to changes in ve. CONCLUSIONS: The decrease in EER after anti-TNF alpha treatment is largely caused by reductions in the volume transfer constant Ktrans, the fractional plasma volume vp, and the T1 relaxation time. Only the contributions from Ktrans and vp directly reflect synovial vascularity.

Pharmacokinetic modeling of dynamic contrast-enhanced MRI of the hand and wrist in rheumatoid arthritis and the response to anti-tumor necrosis factor-alpha therapy.

Dynamic contrast-enhanced MRI (DCE-MRI) of the hand and wrist was performed in 11 patients with rheumatoid arthritis twice before and once 2 weeks after treatment with anti-tumor necrosis factor (TNF)-alpha therapy. A rapid, T1-weighted 3D spoiled gradient echo (SPGR) sequence was used for the dynamic imaging. T1 estimation was performed using similar images obtained at different flip angles. The relative radiofrequency field was estimated from the known T1 of the periarticular fatty marrow. The arterial input function (AIF) was measured at each examination, and normalized to the expected plasma concentration to reduce partial volume effects. Synovial enhancement was modeled to yield values for Ktrans, ve, and vp. Ktrans and ve showed good reproducibility. There was a significant decrease of about 20% in Ktrans after 2 weeks of treatment. This study demonstrates the potential of DCE-MRI and pharmacokinetic modeling to study early changes in inflammatory activity in rheumatoid arthritis following treatment.

Does the presence of a full-thickness rotator cuff tear influence outcome after proximal humeral fractures?

BACKGROUND: Prevalence of rotator cuff tears increases with advancing age. Despite proximal humeral fractures being common in the elderly, the influence of a coexistent rotator cuff tear on outcome has, to our knowledge, not been previously investigated. This study prospectively assessed whether the presence of a rotator cuff tear in association with a proximal humeral fracture influences functional prognosis. METHODS: Eighty-five patients treated conservatively for proximal humeral fractures were evaluated prospectively with ultrasonography to determine the status of the rotator cuff. Every patient was managed by immobilization in an arm sling for 2 weeks followed by physiotherapy. Functional outcome was measured using the Constant and the Oxford shoulder score, at 3 and 12 months postinjury. RESULTS: There were 43 patients with full-thickness cuff tears and 42 patients with no cuff tear or a partial-thickness tear. Full thickness cuff tears were more frequent in patients more than 60 years old. The outcome scores at 3 and 12 months showed no statistically significant difference for either the Constant or the Oxford shoulder score with regard to cuff integrity. Analysis of these scores showed no correlation between presence or absence of a full-thickness cuff tear and shoulder function. CONCLUSION: The results indicate that rotator cuff integrity is not a predictor of shoulder function at 12 months after proximal humeral fracture, as measured by outcome scores and therefore there is no clinical indication for routine imaging of the rotator cuff in patients for whom conservative management is the preferred treatment option.