Muscle deterioration due to rheumatoid arthritis: assessment by quantitative MRI and strength testing.

OBJECTIVES: RA patients often present with low muscle mass and decreased strength. Quantitative MRI offers a non-invasive measurement of muscle status. This study assessed whether MRI-based measurements of T2, fat fraction, diffusion tensor imaging and muscle volume can detect differences between the thigh muscles of RA patients and healthy controls, and assessed the muscle phenotype of different disease stages. METHODS: Thirty-nine RA patients (13 'new RA'-newly diagnosed, treatment naïve, 13 'active RA'-persistent DAS28 >3.2 for >1 year, 13 'remission RA'-persistent DAS28 <2.6 for >1 year) and 13 age and gender directly matched healthy controls had an MRI scan of their dominant thigh. All participants had knee extension and flexion torque and grip strength measured. RESULTS: MRI T2 and fat fraction were higher in the three groups of RA patients compared with healthy controls in the thigh muscles. There were no clinically meaningful differences in the mean diffusivity. The muscle volume, handgrip strength, knee extension and flexion were lower in all three groups of RA patients compared with healthy controls. CONCLUSION: Quantitative MRI and muscle strength measurements can potentially detect differences within the muscles between RA patients and healthy controls. These differences may be seen in RA patients who are yet to start treatment, those with persistent active disease, and those who were in clinical remission. This suggests that the muscles in RA patients are affected in the early stages of the disease and that signs of muscle pathology and muscle weakness are still observed in clinical remission.

MRI for Detecting Root Avulsions in Traumatic Adult Brachial Plexus Injuries: A Systematic Review and Meta-Analysis of Diagnostic Accuracy.

Background Traumatic brachial plexus injuries affect 1% of patients involved in major trauma. MRI is the best test for traumatic brachial plexus injuries, although its ability to differentiate root avulsions (which require urgent reconstructive surgery) from other types of nerve injury remains unknown. Purpose To evaluate the accuracy of MRI for diagnosing root avulsions in adults with traumatic brachial plexus injuries. Materials and Methods For this systematic review, MEDLINE and Embase were searched from inception to August 20, 2018. Studies of adults with traumatic nonpenetrating unilateral brachial plexus injuries were included. The target condition was root avulsion. The index test was preoperative MRI, and the reference standard was surgical exploration. A bivariate meta-analysis was used to estimate summary sensitivities and specificities of MRI for avulsion. Results Eleven studies of 275 adults (mean age, 27 years; 229 men) performed between 1992 and 2016 were included. Most participants had been injured in motorcycle collisions (84%). All studies were at risk of bias, and there were high applicability concerns for the index test (ie, MRI) in four studies given the lack of diagnostic criteria, inadequate descriptions of pulse sequences, and multiplicity of reporting radiologists. Overall, 72% of patients with brachial plexus injuries had at least one root avulsion (interquartile range [IQR]: 53%-86%); meta-analysis of patient-level data was not performed because of sparse and heterogeneous data. With the nerve root as the unit of analysis, 583 of 918 roots were avulsed (median, 55%; IQR: 38%-71%); the mean sensitivity of MRI for root avulsion was 93% (95% confidence interval [CI]: 77%, 98%) with a mean specificity of 72% (95% CI: 42%, 90%). Conclusion On the basis of limited data, MRI offers modest diagnostic accuracy for traumatic brachial plexus root avulsion(s), and early surgical exploration should remain as the preferred method of diagnosis. Published under a CC BY 4.0 license. Online supplemental material is available for this article.

High-resolution MRI assessment of dactylitis in psoriatic arthritis shows flexor tendon pulley and sheath-related enthesitis.

OBJECTIVE: Dactylitis is a hallmark of psoriatic arthritis (PsA) where flexor tenosynovitis is common. This study explored the microanatomical basis of dactylitis using high-resolution MRI (hrMRI) to visualise the small entheses around the digits. METHODS: Twelve patients with psoriatic dactylitis (4 fingers, 8 toes), and 10 healthy volunteers (6 fingers, 4 toes) had hrMRI of the digits using a 'microscopy' coil and contrast enhancement. All structures were evaluated including the tendons and ligaments, related enthesis organs, pulleys, volar/plantar plates and tendon sheaths. RESULTS: In dactylitis, collateral ligament enthesitis was seen in nine digits (75%), extensor tendon enthesitis in six digits (50%), functional enthesitis (5 digits, 42%), abnormal enhancement at the volar plates (2/5 joints, 40%) and the plantar plate (1/5 joints, 20%). Nine cases (75%) demonstrated flexor tenosynovitis, with flexor tendon pulley/flexor sheath microenthesopathy observed in 50% of all cases. Less abnormalities which were milder was observed in the normal controls, none of whom had any signal changes in the tendon pulleys or fibrous sheaths. CONCLUSIONS: This study provides proof of concept for a link between dactylitis and 'digital polyenthesitis' including disease of the miniature enthesis pulleys of the flexor tendons, further affirming the concept of enthesitis in PsA.

Gadofosveset-based biomarker of tissue albumin concentration: Technical validation in vitro and feasibility in vivo.

PURPOSE: There is currently no adequate method of mapping physiologic and pathophysiologic tissue albumin concentrations in human subjects. The objective of this study was to devise and evaluate a biomarker of regional albumin concentration using gadofosveset-enhanced MRI. THEORY AND METHODS: A binding and relaxation model was devised and evaluated in vitro in solutions of albumin at 3.0 Tesla (T) and 4.7T. The method was evaluated in the heart in seven volunteers at 3.0T. RESULTS: MRI-derived estimates of albumin concentration were in good agreement with true values over the range 0.1-1.0 mM (Pearson correlation coefficients of 0.85 and 0.88 for 3.0T and 4.7T, respectively). The mean calculated albumin concentration in the myocardium for the volunteers was 0.02 mM (range, 0.01-0.03 mM). CONCLUSION: Accurate estimates of albumin concentration in vitro suggest this may be a viable noninvasive alternative to existing techniques. In the myocardium the MRI-derived estimates of albumin concentration indicate the practical feasibility of the technique but were below expected values. Gadofosveset-enhanced MR relaxometry has potential in providing biomarkers of regional albumin concentration; further evaluation is required before it can be used reliably in vivo.

High-resolution [18F]fluoride positron emission tomography of the distal interphalangeal joint in psoriatic arthritis--a bone-enthesis-nail complex.

OBJECTIVE: This study used high-resolution PET to explore the pattern of DIP joint bone metabolism to test the hypothesis that the nail was functionally integrated with the bone, based on patterns of distal phalange (DP) bone metabolism in PsA compared with OA and normal joints. METHODS: A total of 234 DIP joints were scanned in 30 subjects (10 PsA, 10 OA, 10 healthy control) with [18F]fluoride using the quad-high-density avalanche chamber nano PET scanner. The images were assessed blinded to diagnosis and symptoms for site and intensity of increased [18F]fluoride uptake. RESULTS: [18F]fluoride uptake in the DP was strong relative to the intermediate phalange in both PsA and OA. In PsA there was a trend for uptake to occur in a diffuse pattern involving the entire DP. There was also greater uptake at the enthesis, the periosteum and at the tufts of the DP of PsA compared with OA. In OA, uptake was greatest in the subchondral region adjacent to known sites of osteophytosis and erosions. Both PsA and OA joints with uptake at the subchondral or periosteal bone are likely to be more symptomatic. CONCLUSION: This exploratory study suggested diffuse increased bone metabolism involving the entire DP, periosteum and entheses, especially in PsA. The subchondral bone and periosteum at the DP have large concentrations of enthesis attachments, including attachments from the nail, supporting the concept of an integrated nail and joint apparatus leading to a wide area of abnormal bone metabolism in PsA.

Visualization and quantification of whole rat heart laminar structure using high-spatial resolution contrast-enhanced MRI.

It has been shown by histology that cardiac myocytes are organized into laminae and this structure is important in function, both influencing the spread of electrical activation and enabling myocardial thickening in systole by laminar sliding. We have carried out high-spatial resolution three-dimensional MRI of the ventricular myolaminae of the entire volume of the isolated rat heart after contrast perfusion [dimeglumine gadopentate (Gd-DTPA)]. Four ex vivo rat hearts were perfused with Gd-DTPA and fixative and high-spatial resolution MRI was performed on a 9.4T MRI system. After MRI, cryosectioning followed by histology was performed. Images from MRI and histology were aligned, described, and quantitatively compared. In the three-dimensional MR images we directly show the presence of laminae and demonstrate that these are highly branching and are absent from much of the subepicardium. We visualized these MRI volumes to demonstrate laminar architecture and quantitatively demonstrated that the structural features observed are similar to those imaged in histology. We showed qualitatively and quantitatively that laminar architecture is similar in the four hearts. MRI can be used to image the laminar architecture of ex vivo hearts in three dimensions, and the images produced are qualitatively and quantitatively comparable with histology. We have demonstrated in the rat that: 1) laminar architecture is consistent between hearts; 2) myolaminae are absent from much of the subepicardium; and 3) although localized orthotropy is present throughout the myocardium, tracked myolaminae are branching structures and do not have a discrete identity.

Influence of cellulose on ion diffusivity in 1-ethyl-3-methyl-imidazolium acetate cellulose solutions.

Solutions of microcrystalline cellulose in 1-ethyl-3-methyl-imidazolium acetate have been investigated using pulsed-field gradient (1)H NMR. In all cases the geometrically larger cation was found to diffuse faster than the smaller anion. Arrhenius temperature analysis has been applied to the ion diffusivities giving activation energies. The diffusion and published viscosity data for these solutions were shown to follow the Stokes-Einstein relationship, giving hydrodynamic radii of 1.6 Š(cation) and 1.8 Š(anion). Theories for obstruction, free-volume and hydrodynamic effects on solvent diffusion have been applied. The Mackie-Meares and Maxwell-Fricke obstruction models provided a correct trend only when assuming a certain fraction of ions are bound to the polymer. From this fraction it was shown that the maximum dissolvable cellulose concentration is ∼27% w/w, which is consistent with the highest known prepared concentration of cellulose in this ionic liquid. The Phillies' hydrodynamic model is found to give the best description for the cellulose concentration dependence of the ion diffusivities.

Diffusion Tensor Imaging for Diagnosing Root Avulsions in Traumatic Adult Brachial Plexus Injuries: A Proof-of-Concept Study.

Cross-sectional MRI has modest diagnostic accuracy for diagnosing traumatic brachial plexus root avulsions. Consequently, patients either undergo major exploratory surgery or months of surveillance to determine if and what nerve reconstruction is needed. This study aimed to develop a diffusion tensor imaging (DTI) protocol at 3 Tesla to visualize normal roots and identify traumatic root avulsions of the brachial plexus. Seven healthy adults and 12 adults with known (operatively explored) unilateral traumatic brachial plexus root avulsions were scanned. DTI was acquired using a single-shot echo-planar imaging sequence at 3 Tesla. The brachial plexus was visualized by deterministic tractography. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated for injured and avulsed roots in the lateral recesses of the vertebral foramen. Compared to healthy nerves roots, the FA of avulsed nerve roots was lower (mean difference 0.1 [95% CI 0.07, 0.13]; p < 0.001) and the MD was greater (mean difference 0.32 × 10-3 mm2/s [95% CI 0.11, 0.53]; p < 0.001). Deterministic tractography reconstructed both normal roots and root avulsions of the brachial plexus; the negative-predictive value for at least one root avulsion was 100% (95% CI 78, 100). Therefore, DTI might help visualize both normal and injured roots of the brachial plexus aided by tractography. The precision of this technique and how it relates to neural microstructure will be further investigated in a prospective diagnostic accuracy study of patients with acute brachial plexus injuries.

An In Vitro Study of the Intervertebral Disc Structure Using 3 T Magnetic Resonance Imaging.

STUDY DESIGN: An in vitro magnetic resonance imaging (MRI) study. OBJECTIVE: Investigate the potential of high-field MRI for producing higher quality images of the intervertebral disc (IVD) to better distinguish structural details. SUMMARY OF BACKGROUND DATA: Higher spatial and contrast resolution are important advantages when imaging the complex tissue structures in the spine such as the IVDs. However, at present it is challenging to capture the substructural details in the IVD such as the lamellae. METHODS: Three MRI sequences; two-dimensional proton-density-weighted Turbo-Spin-Echo (PD-TSE), 2D T2-weighted Turbo-Spin-Echo (T2W-TSE) with fat-saturation (FS), and 3D Spoiled-Gradient-Echo (3D-GE), were modified based on the image quality and scan duration. IVDs of three intact cadaveric lumbar-spines (T12-S1, Age 83-94 yr) were imaged using these optimized sequences. Thereafter each IVD was transversely sectioned and the exposed surfaces were photographed. Landmark observations from corresponding MRI slices and photographs were compared to confirm the MRI captured morphology. The image quality was evaluated using signal-to-noise ratio (SNR), and relative-contrast values. Finally, the underlying tissue structures, including specific pathological features, were qualitatively compared between the MR images and photographs. RESULTS: Observations from photographs and corresponding MRI slices matched well. The PD-TSE sequence had better overall SNR, but the relative contrast between the tissue types was relatively poor. The 3D-GE sequence had higher relative contrast between the IVD and bone, but not between annulus and nucleus regions. The T2W images provided the best relative contrast between the annulus and nucleus, however the standard deviations here were high. Structural details including fissures, vascular and granular tissue proliferation, and pathologies in the endplate region, were identifiable from the MR images obtained using the optimized sequences. CONCLUSION: The results demonstrate the potential of high-field MRI to capture the IVD structural details. Since the acquisition durations were within clinically acceptable levels, these methodological improvements have the potential to enhance clinical diagnostics. LEVEL OF EVIDENCE: 4.

Normal values and test-retest variability of stimulated-echo diffusion tensor imaging and fat fraction measurements in the muscle.

OBJECTIVES: To assess the test-retest variability of both diffusion parameters and fat fraction (FF) estimates in normal muscle, and to assess differences in normal values between muscles in the thigh. METHODS: 29 healthy volunteers (mean age 37 years, range 20-60 years, 17/29 males) completed the study. Magnetic resonance images of the mid-thigh were acquired using a stimulated echo acquisition mode-echoplanar imaging (STEAM-EPI) imaging sequence, to assess diffusion, and 2-point Dixon imaging, to assess FF. Imaging was repeated in 19 participants after a 30 min interval in order to assess test-retest variability of the measurements. RESULTS: Intraclass correlation coefficients (ICCs) for test-retest variability were 0.99 [95% confidence interval, (CI): 0.98, 1] for FF, 0.94 (95% CI: 0.84, 0.97) for mean diffusivity and 0.89 (95% CI: 0.74, 0.96) for fractional anisotropy (FA). FF was higher in the hamstrings than the quadriceps by a mean difference of 1.81% (95% CI:1.63, 2.00)%, p < 0.001. Mean diffusivity was significantly lower in the hamstrings than the quadriceps (0.26 (0.13, 0.39) x10-3 mm2s-1, p < 0.001) whereas fractional anisotropy was significantly higher in the hamstrings relative to the quadriceps with a mean difference of 0.063 (0.05, 0.07), p < 0.001. CONCLUSIONS: This study has shown excellent test-retest, variability in MR-based FF and diffusion measurements and demonstrated significant differences in these measures between hamstrings and quadriceps in the healthy thigh. ADVANCES IN KNOWLEDGE: Test-retest variability is excellent for STEAM-EPI diffusion and 2-point Dixon-based FF measurements in the healthy muscle. Inter- and intraobserver variability were excellent for region of interest placement for STEAM-EPI diffusion and 2-point Dixon-based FF measurements in the healthy muscle. There are significant differences in FF and diffusion measurements between the hamstrings and quadriceps in the normal muscle.

Use of high-resolution microscopy coil MRI for depicting orbital anatomy.

OBJECTIVE: High-resolution MRI (HR-MRI) is a powerful non-invasive tool that provides images of higher spatial resolution and enables visualization of tissues previously unidentified with conventional techniques. The utilization of HR-MRI in the eye and orbit is essential due to the minute structure with great tissue diversity. The purpose of this study is to investigate the use of a novel surface coil and to explore the potential of this approach to depict normal anatomy. METHODS: MR images were acquired using a commonly available 1.5T scanner. Ten normal volunteers were imaged using a surface microscopy coil of 47 mm inner diameter. T1- and T2-weighting and fat suppression techniques were used. HR-MR images were compared with conventional head coil MR images. RESULTS: Overall exquisite anatomic detail of the eye and orbit is revealed. The in-plane resolution was 312 microm and the displayed pixel dimension 156 microm. Previously unobserved distinction of the globe layers and muscle groups is possible. To our best knowledge, our group was the first to demonstrate Tenon's capsule and the tarsal plate with MRI. The ciliary body and zonules of the lens are clearly visible. The superior muscle group is illustrated, being apparently divided into its components, namely the superior rectus and the levator palpebrae superioris muscles. Finally, the retrobulbar fat and parts of its connective tissue are depicted. CONCLUSION: High-resolution microscopy coil MRI improves the image resolution dramatically and enables a detailed tissue depiction of the orbital and globe structures. Therefore, its introduction in routine clinical use can facilitate diagnosis and pre-operative planning in challenging cases.

Magnetic resonance imaging for detecting root avulsions in traumatic adult brachial plexus injuries: protocol for a systematic review of diagnostic accuracy.

BACKGROUND: Adult brachial plexus injuries (BPI) are becoming more common. The reconstruction and prognosis of pre-ganglionic injuries (root avulsions) are different to other types of BPI injury. Preoperative magnetic resonance imaging (MRI) is being used to identify root avulsions, but the evidence from studies of its diagnostic accuracy are conflicting. Therefore, a systematic review is needed to address uncertainty about the accuracy of MRI and to guide future research. METHODS: We will conduct a systematic search of electronic databases alongside reference tracking. We will include studies of adults with traumatic BPI which report the accuracy of preoperative MRI (index test) against surgical exploration of the roots of the brachial plexus (reference standard) for detecting either of the two target conditions (any root avulsion or any pseudomeningocoele as a surrogate marker of root avulsion). We will exclude case reports, articles considering bilateral injuries and studies where the number of true positives, false positives, false negatives and true negatives cannot be derived. The methodological quality of the included studies will be assessed using a tailored version of the QUADAS-2 tool. Where possible, a bivariate model will be used for meta-analysis to obtain summary sensitivities and specificities for both target conditions. We will investigate heterogeneity in the performance of MRI according to field strength and the risk of bias if data permits. DISCUSSION: This review will summarise the current diagnostic accuracy of MRI for adult BPI, identify shortcomings and gaps in the literature and so help to guide future research. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42016049702 .

Posterior fossa abnormalities seen on magnetic resonance brain imaging in a cohort of newborn infants.

OBJECTIVE: To describe the nature and frequency of posterior fossa (PF) lesions in infants who underwent magnetic resonance (MR) brain imaging in the neonatal period and to correlate with cranial ultrasound (CUS) findings and clinical outcome. STUDY DESIGN: A retrospective review of all neonatal MR brain imaging from 1996 to 2001 (n=558). MR images, CUS and case notes were reviewed in infants with PF abnormality. RESULTS: A total of 20 infants had abnormalities in the PF, which represents 4.7% of abnormalities seen on MR. Out of 10, six term infants had PF extra-axial hemorrhage, three had cerebellar hypoplasia, while one had cerebellar hemorrhage. In the preterm, 8/10 lesions were unilateral; focal cerebellar hemorrhage was seen in 5/10 and extensive hemorrhage with secondary atrophy in 3/10. Out of 20, 17 infants also had supratentorial lesions. Out of 20, 19 had CUS performed, of which 7/19 showed PF abnormality. CONCLUSION: Intracerebellar hemorrhage was more common in preterm infants than in term infants. These hemorrhages tended to be focal, unilateral and were associated with atrophy.

The microanatomic basis of finger clubbing - a high-resolution magnetic resonance imaging study.

OBJECTIVE: Hypervascularization in finger clubbing is recognized, but its microanatomical basis remains unclear. This pilot descriptive study used magnetic resonance imaging (MRI) to explore this further. METHODS: High-resolution MRI acquired with contrast agent was carried out in 4 patients with finger clubbing and 4 healthy volunteers. The anatomy of the nail bed, capsular structures, and bony changes were described. RESULTS: Marked nail bed thickening and contrast enhancement was noted in all clubbed fingers, with bone edema in 3 of the 4 patients. None of the healthy subjects had similar abnormalities. CONCLUSION: This confirms that hypervascularization of the nail bed observed in the microanatomy on high-resolution MRI is associated with clubbed appearances of the nails.

The effects of iron oxide incorporation on the chondrogenic potential of three human cell types.

Non-invasive monitoring of living cells in vivo provides an important tool in the development of cell-based therapies in cartilage tissue engineering. High-resolution magnetic resonance imaging (MRI) has been used to monitor target cell populations in vivo. However, the side-effects on cell function of the labelling reagents, such as superparamagnetic iron oxide (SPIO), are still unclear. This study investigated the effect of SPIO particles on the chondrogenic differentiation of human bone marrow stromal cells (HBMSCs), neonatal and adult chondrocytes in vitro. Cells were labelled with SPIO for 24 h and chondrogenesis induced in serum-free medium including TGFß3. For labelled/unlabelled cells, viability, morphology and proliferation were determined using CellTracker™ Green and PicoGreen dsDNA assays. The expression of SOX9, COL2A1 and ACAN was investigated using qRT-PCR after 2, 7 and 14 days. The results showed that viability was unaffected in all of the cells but cell morphology changed towards a 'stretched' phenotype following SPIO uptake. Cell proliferation was reduced only for labelled neonatal chondrocytes. SOX9 and COL2A1 expression decreased at day 2 but not at days 7 and 14 for labelled HBMSCs and adult chondrocytes; ACAN expression was unaffected. In contrast, SOX9 and COL2A1 expression were unaffected in labelled neonatal chondrocytes but a decrease in ACAN expression was seen at day 14. The results suggest that downregulation of chondrogenic genes associated with SPIO labelling is temporary and target cell-dependent. Resovist® can be used to label HBMSCs or mature chondrocytes for MR imaging of cells for cartilage tissue engineering.

Combining variational and model-based techniques to register PET and MR images in hand osteoarthritis.

Co-registration of clinical images acquired using different imaging modalities and equipment is finding increasing use in patient studies. Here we present a method for registering high-resolution positron emission tomography (PET) data of the hand acquired using high-density avalanche chambers with magnetic resonance (MR) images of the finger obtained using a 'microscopy coil'. This allows the identification of the anatomical location of the PET radiotracer and thereby locates areas of active bone metabolism/'turnover'. Image fusion involving data acquired from the hand is demanding because rigid-body transformations cannot be employed to accurately register the images. The non-rigid registration technique that has been implemented in this study uses a variational approach to maximize the mutual information between images acquired using these different imaging modalities. A piecewise model of the fingers is employed to ensure that the methodology is robust and that it generates an accurate registration. Evaluation of the accuracy of the technique is tested using both synthetic data and PET and MR images acquired from patients with osteoarthritis. The method outperforms some established non-rigid registration techniques and results in a mean registration error that is less than approximately 1.5 mm in the vicinity of the finger joints.

High resolution magnetic resonance imaging of excised atherosclerotic carotid tissue: the effects of specimen temperature on image contrast.

Previous Magnetic Resonance (MR) studies of carotid endarterectomy (CEA) specimens have been directed at interpreting image contrast to determine plaque composition and stability. Such studies may give misleading results since it is believed that the acquired MR data is affected by the conditions used to store the excised tissue. This has been investigated in a high-resolution imaging study of the changes in contrast occurring with a change in specimen temperature. MR images were acquired from 20 CEA specimens. The initial MR examination was made within four hours of excision in tissue maintained and imaged at body temperature. Specimens were subsequently cooled and then re-examined at different times. The MR data was interpreted by comparison with histology obtained from equivalent sections. With the exception of signals arising from blood, changes in MR image contrast occurring in the 24-hour period after the CEA were relatively slight. Plaque lipid T2-weighted image intensity was initially relatively hyperintense in some samples and decreased with time on cooling reflecting a decrease in the lipid transverse (T2) relaxation time. High-resolution imaging allowed a detailed description of plaque calcification and showed that clot retraction was probably responsible for the marked change in the distribution of signals assigned to intraluminal blood. The use of high-resolution MR imaging to examine freshly excised specimens at body temperature showed previously unreported image features. This is important in the design of in vivo MR studies directed at assessing plaque stability by identifying the composition of the atheromatous tissue.

Efficacy of infliximab on MRI-determined bone oedema in psoriatic arthritis.

BACKGROUND: Psoriatic arthritis (PsA) is commonly associated with bone pathology, including entheseal new bone formation and osteolysis. On MRI, areas of active clinical involvement are represented by bone oedema and synovitis. AIM: To assess the impact of infliximab on bone oedema in PsA as shown by MRI. METHODS: 18 patients with joint swelling, psoriasis and seronegativity for rheumatoid factor received four infusions of infliximab, 3 mg/kg, in combination with methotrexate. MRI of the affected hand (12 patients) or knee joints (6 patients) was performed before and after treatment. The primary outcome was the assessment of bone oedema and synovitis at 20 weeks as shown by MRI. Secondary outcomes included the American College of Rheumatology (ACR) response criteria, psoriasis skin scores (Psoriasis Area and Severity Index (PASI)) and a quality of life measure (Psoriatic Arthritis Quality of Life (PsAQoL)). RESULTS: At baseline, bone oedema was seen in 50% of patients (seven hands and two knees) in 30% of scanned joints, and this improved or resolved in all cases in the hand joints (p = 0.018) and in one knee joint at 20 weeks. Synovitis was found to be reduced in 90% of cases on MRI. Likewise, a significant improvement in all clinical outcomes, including PASI (p = 0.003) and PsAQoL (p = 0.006) was seen at week 20. 65% (n = 11) of the patients achieved an ACR response, of whom 45% had ACR70 or above and 54% had ACR20 or ACR50. CONCLUSIONS: Infliximab treatment is associated with dramatic improvements in MRI-determined bone oedema in PsA in the short term. It remains to be determined whether infliiximib treatment is the cause for prevention of new bone formation, bone fusion or osteolysis in PsA as shown by radiography.

Evidence for a different anatomic basis for joint disease localization in polymyalgia rheumatica in comparison with rheumatoid arthritis.

OBJECTIVE: The anatomic basis for joint disease localization in polymyalgia rheumatica (PMR) is poorly understood. This study used contrast-enhanced and fat suppression magnetic resonance imaging (MRI) to evaluate the relationship between synovial and extracapsular inflammation in PMR and early rheumatoid arthritis (RA). METHODS: Ten patients with new-onset PMR and 10 patients with early RA underwent dynamic contrast-enhanced MRI and conventional MRI of affected metacarpophalangeal (MCP) joints. Synovitis and tenosynovitis were calculated based on the number of enhancing voxels, initial rate of enhancement, and maximal enhancement of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). Periarticular bone erosion and bone edema were scored according to the OMERACT (Outcome Measures in Rheumatology Clinical Trials) scoring system in both groups. The degree of extracapsular Gd-DTPA enhancement was assessed in both conditions using semiquantitative scoring. RESULTS: No significant differences were seen in the volume of synovitis (P = 0.294), degree of flexor tenosynovitis (P = 0.532), periarticular erosions (P = 0.579), or degree of bone edema (P = 0.143) between RA and PMR joints. However, despite comparable degrees of synovitis, the proportion of MCP joints showing extracapsular enhancement was higher in the PMR group (100%) than in the RA group (50%) (P = 0.030). One PMR patient, but none of the RA patients, had bone edema at the capsular insertion. CONCLUSION: Despite degrees of synovitis and tenosynovitis comparable with those in RA, PMR-related hand disease is associated with prominent extracapsular changes, suggesting that inflammation in these tissues is more prominent than joint synovitis, which is common in both conditions. This suggests that the anatomic basis for joint disease localization differs between RA and PMR.