Magnetic resonance imaging of peripheral joints in rheumatic diseases

The need for better methods than the conventional clinical, biochemical and radiographical examinations in the management of inflammatory joint diseases is evident, since these methods are not sensitive or specific to early pathologies and subtle changes. Magnetic resonance imaging (MRI) offers improved sensitivity to early inflammatory and destructive changes in peripheral joints in rheumatoid arthritis (RA) and, even though less well documented, in other inflammatory joint diseases. Good evidence is available that MRI bone erosions represent true bone abnormalities and are predictors of radiographical outcome in RA. Similarly, there is solid evidence for MRI synovitis representing true synovial inflammation and being of considerable practical, clinical and radiological significance in RA. Describing the encouraging current knowledge regarding MRI for diagnosis, monitoring and prognosis, this chapter discusses the potential for the use of MRI in the clinical management of patients with suspected and diagnosed inflammatory joint diseases, as well as research priorities and clinical situations where the use of MRI could be suggested.     

Magnetic resonance imaging of wrist and finger joints in healthy subjects occasionally shows changes resembling erosions and synovitis as seen in rheumatoid arthritis

OBJECTIVE: To explore the presence of changes resembling rheumatoid arthritis erosions and synovitis in metacarpophalangeal (MCP) and wrist joints of healthy individuals on magnetic resonance imaging (MRI) and to compare the MRI findings with conventional radiographic, clinical, and biochemical findings. METHODS: Twenty-eight healthy individuals were studied. Contrast-enhanced MRI and conventional radiography of the dominant wrist and second through fifth MCP joints were performed, coupled with standard clinical assessments and biochemical analyses. MR images were evaluated according to the latest OMERACT (Outcome Measures in Rheumatology Clinical Trials) recommendations with respect to synovitis, erosions, and bone marrow edema. RESULTS: Conventional radiography revealed erosion-like changes in 1 of 224 MCP joint bones (0.4%) and in 1 of 420 wrist joint bones (0.2%). MRI depicted low-grade erosion-like changes in 5 of 224 MCP joint bones (2.2%) and in 7 of 420 wrist joint bones (1.7%), but postcontrast enhancement within the lesion was detected in only 8.3% of these. MRI depicted low-grade synovitis-like changes in 10 of 112 MCP joints (8.9%) and in 8 of 84 assessed wrist areas (9.5%), while only minimal early synovial enhancement was detected by dynamic MRI. Three subjects had elevated serum levels of C-reactive protein, and these subjects displayed 44.5% of the synovitis-like changes and 41.7% of the erosion-like changes. Bone marrow edema-like changes were not found in any joints. CONCLUSION: Changes resembling mild synovitis or small bone erosions are occasionally found in the MCP and wrist joints of healthy controls. Signs of synovitis on dynamic MRI, enhancement within bone erosion-like changes, and signs of bone marrow edema appear rarely or are absent in healthy controls. These signs may thus prove to be very specific in the distinction between arthritic and normal joints.     

Variation and association to diabetes in 2000 full mtDNA sequences mined from an exome study in a Danish population

In this paper, we mine full mtDNA sequences from an exome capture data set of 2000 Danes, showing that it is possible to get high-quality full-genome sequences of the mitochondrion from this resource. The sample includes 1000 individuals with type 2 diabetes and 1000 controls. We characterise the variation found in the mtDNA sequence in Danes and relate the variation to diabetes risk as well as to several blood phenotypes of the controls but find no significant associations. We report 2025 polymorphisms, of which 393 have not been reported previously. These 393 mutations are both very rare and estimated to be caused by very recent mutations but individuals with type 2 diabetes do not possess more of these variants. Population genetics analysis using Bayesian skyline plot shows a recent history of rapid population growth in the Danish population in accordance with the fact that >40% of variable sites are observed as singletons.     

Extensive X-linked adaptive evolution in central chimpanzees

Surveying genome-wide coding variation within and among species gives unprecedented power to study the genetics of adaptation, in particular the proportion of amino acid substitutions fixed by positive selection. Additionally, contrasting the autosomes and the X chromosome holds information on the dominance of beneficial (adaptive) and deleterious mutations. Here we capture and sequence the complete exomes of 12 chimpanzees and present the largest set of protein-coding polymorphism to date. We report extensive adaptive evolution specifically targeting the X chromosome of chimpanzees with as much as 30% of all amino acid replacements being adaptive. Adaptive evolution is barely detectable on the autosomes except for a few striking cases of recent selective sweeps associated with immunity gene clusters. We also find much stronger purifying selection than observed in humans, and in contrast to humans, we find that purifying selection is stronger on the X chromosome than on the autosomes in chimpanzees. We therefore conclude that most adaptive mutations are recessive. We also document dramatically reduced synonymous diversity in the chimpanzee X chromosome relative to autosomes and stronger purifying selection than for the human X chromosome. If similar processes were operating in the human-chimpanzee ancestor as in central chimpanzees today, our results therefore provide an explanation for the much-discussed reduction in the human-chimpanzee divergence at the X chromosome.     

After treat-to-target: can a targeted ultrasound initiative improve RA outcomes?

For patients with rheumatoid arthritis (RA), remission can be achieved with tight control of inflammation and early use of disease modifying agents. The importance of remission as an outcome has been recently highlighted by European League Against Rheumatism recommendations. However, remission when defined by clinical remission criteria (disease activity score, simplified disease activity index, etc) does not always equate to the complete absence of inflammation as measured by new sensitive imaging techniques such as ultrasound (US) . There is evidence that imaging synovitis is frequently found in these patients and associated with adverse clinical and functional outcomes. This article reviews the data regarding remission, ultrasound imaging and outcomes in patients with RA to provide the background to a consensus statement from an international collaboration of ultrasonographers and rheumatologists who have recently formed a research network--the Targeted Ultrasound Initiative (TUI) group. The statement proposes that targeting therapy to PD activity provides superior outcomes compared with treating to clinical targets alone and introduces the rationale for a new randomised trial using targeted ultrasound in RA.     

Correlations and agreement between delta-9-tetrahydrocannabinol (THC) in blood plasma and timeline follow-back (TLFB)-assisted self-reported use of cannabis of patients with cannabis use disorder and psychotic illness attending the CapOpus randomized clinical trial

Aims To assess correlations and agreement between timeline follow‐back (TLFB)‐assisted self‐report and blood samples for cannabis use. Design Secondary analysis of a randomized trial. Setting Copenhagen, Denmark. Participants One hundred and three patients from the CapOpus trial with cannabis use disorder and psychosis, providing 239 self‐reports of cannabis use and 88 valid blood samples. Measurements Delta‐9‐tetrahydrocannabinol (THC), 11‐hydroxy‐delta‐9‐tetrahydrocannabinol (11‐OH‐THC) and 11‐nor‐delta‐9‐tetrahydrocannabinol‐9‐carboxylic acid (THC‐COOH) detected in plasma using high‐performance liquid chromatography with tandem mass spectrometry detection. Self‐report of cannabis‐use last month by TLFB. Pearson's r, sensitivity and specificity calculated as measures of correlation or agreement. Findings Correlations were strong; r = 0.75 for number of days and r = 0.83 for number of standard joints in the preceding month when excluding outliers. Including outliers, coefficients were moderate to strong (r = 0.49). There were differences in subgroups, mainly inconsistent, depending on inclusion or exclusion of outliers. Sensitivity and specificity for TLFB detecting the presence or absence of cannabis use were 95.7% [95% confidence interval (CI) 88.0–99.1%) and 72.2% (95% CI 46.5–90.3%), respectively. Using 19 days as cut‐off on TLFB, they were 94.3% (95% CI 86.0–98.4%) and 94.4% (95% CI 72.2–99.9%), respectively. Area under the receiver operating characteristic (ROC) curve was 0.96. Conclusions Timeline follow‐back (TLFB)‐assisted self‐report of cannabis use correlates highly with plasma‐delta‐9‐tetrahydrocannabinol in patients with comorbid cannabis use disorder and psychosis. Sensitivity and specificity of timeline follow‐back appear to be optimized with 19 days as the cut‐off point. As such, timeline follow‐back may be superior to analysis of blood when going beyond 19 days of recall.     

High bone mineral apparent density in children with X-linked hypophosphatemia

Summary

Bone mineral apparent density (BMAD) in children with X-linked hypophosphatemia (XLH) was evaluated, as they are unlikely to have extra-skeletal ossifications contributing to the elevated bone mineral density of the spine in adult patients. Children with XLH also had significantly higher BMAD of the spine compared to femoral neck.

Introduction

BMAD obtained by dual-energy X-ray absorptiometry scans in children with XLH was evaluated, as they are unlikely to have the extra-skeletal ossifications contributing to the elevated bone mineral density of the spine in adult patients.

Methods

A total of 15 children with biochemically and genetically verified XLH were recruited. Anthropometric measurements were performed, and to correct for the short stature (small bones), the BMAD of the spine and the femoral neck was evaluated.

Results

Z-scores of BMAD of the spine (mean (95 % CI); 2.0 (1.3–2.7); p?<?0.001) were significantly elevated compared to reference children. Z-scores of the femoral neck (1.0 (?0.0 to 2.1); p?=?0.059) tended to be elevated. Spine Z-scores were significantly higher than the Z-scores of the femoral neck, (paired t test, p?=?0.02). BMAD of the spine was evaluated according to the Molgaard’s approach; XLH children had normal bone size of the spine for age due to a normal sitting height Z-score of ?0.4 (?1.0 to 0.1); p?=?0.1. Z-scores of bone mineral content (BMC) of the spine for bone area were elevated (1.4 (0.8–2.1); p?<?0.001). No reference data were available to allow evaluation of the BMAD of the femoral neck by the Molgaard's approach.

Conclusions

Children with XLH have an increased BMAD and a high BMC for bone area at the lumbar spine, and this was due to causes other than extra-skeletal ossifications and corrected for bone size. The BMAD of the spine was significantly higher compared to the femoral neck.