Torsten Diekhoff

Active inflammation and structural change in early active axial spondyloarthritis as detected by whole-body MRI

Objective To evaluate active inflammatory lesions (AIL) and structural changes (SC) in patients with active non-radiographic axial spondyloarthritis (nr-axSpA) compared with patients with ankylosing spondylitis (AS) on whole-body MRI (wb-MRI). Method 75 patients with active disease and a symptom duration of <5 years (39 with AS and 36 with nr-axSpA) were investigated with a comprehensive wb-MRI protocol and scored for AIL and SC in the spine, sacroiliac joints (SIJs) and non-axial manifestations. Results 92% of patients with AS showed active inflammation in the SIJ, 53% in the spine and 94% and 39%, respectively, in the nr-axSpA group. There was a non-significant trend towards more inflammation in patients with AS compared with patients with nr-axSpA in SIJs and spine. Peripheral enthesitis/osteitis was more common in patients with AS (n=22) than in those with nr-axSpA (n=12) (p=0.05). SC were more common in patients with AS than in those with nr-axSpA, with significantly higher scores for SIJ fatty bone marrow deposition (FMD) in patients with AS (4.8±3.2) compared with those with nr-axSpA (2.4±2.7; p=0.001) and more frequent bone proliferation in the spine and the SIJ (p=0.02 and p=0.005, respectively). SIJ erosions were more common in AS (score 4.2±2.3) than in nr-axSpA (score 3.8±1.8) patients (not significant). Conclusions Wb-MRI detects active inflammation and SC more frequently in the SIJs than in the spine. Half of the patients showed inflammation in non-axial sites. Active inflammatory and structural lesions were present both in patients with AS and those with nr-axSpA, being only slightly more common in patients with AS.

Diffusion tensor imaging in hydrocephalus—findings before and after shunt surgery

BackgroundTo evaluate changes in diffusion tensor imaging (DTI)-derived parameters in patients with hydrocephalus (HC) before and several weeks after shunt surgery.MethodsThirteen HC patients were examined with DTI before and after shunt surgery. In a combined region of interest and whole brain voxel-based analysis, different DTI parameters were compared with an age-matched control group.ResultsAlteration of DTI parameters in HC patients and changes after shunt surgery are regionally different. HC patients show an increase in fractional anisotropy values based on increases in parallel diffusivity in the corticospinal tract. On the other hand, reduced fractional anisotropy values are found in the corpus callosum of HC patients. Following shunt surgery, all DTI parameters showed a trend towards normalization, yet differences to healthy control subjects remained.ConclusionOur results show that DTI parameter changes are regionally dependent and need a careful interpretation of the underlying diffusivities to serve as a diagnostic or follow-up measure in patients with hydrocephalus.

Detection and characterization of crystal suspensions using single-source dual-energy computed tomography: a phantom model of crystal arthropathies.

ObjectivesThe aim of this study was to perform phantom measurements to prove the feasibility of single-source dual-energy computed tomography (DECT) of the extremities using a volume scan mode. In addition, we, for the first time, wanted to determine which concentrations of monosodium urate (MSU) in gout and calcium pyrophosphate (CP) in pseudogout are needed to detect or distinguish these soft tissue depositions with DECT. Materials and MethodsWe created a hand-shaped plastic phantom assembled with a descending order of concentrations of MSU (6.25%–50%) and CP (1.56%–50%) with similar attenuation in conventional computed tomographic (CT) images. Dual-energy imaging was done on a standard 320-row CT scanner with acquisition of 2 volumes: one at 80 and the other at 135 kV. Using linear regression analysis, dual-energy gradients were calculated for MSU and CP. Thereafter, we selected a specific region of interest on the dual-energy graph to color-code MSU and CP on the images. Three blinded readers scored 10 scans of the randomly equipped phantom, corresponding to 60 samples, to determine the sensitivity and specificity of this technique. Receiver operating characteristics analysis was done to determine the diagnostic power. ResultsWe found a dual-energy gradient for MSU of 1.020 ± 0.006 and for CP of 0.673 ± 0.001. Assessment of the randomized phantom scans indicates reliable detection of MSU at concentrations of 12.5 % or higher and that of CP at 6.25 % or higher, corresponding to deposits with mean Hounsfield unit values of 59.8 for MSU and 101.1 for CP. The sensitivity for MSU ranged from 83.3% to 97.3% at 15/90 mA (135/80 kV) and from 86.7% to 97.3% at 100/570 mA. Specificity was 96.7% to 100% in 15/90 mA and 100% in 100/570 mA of scans. However, there was inferior sensitivity for CP owing to lower concentrations. In the receiver operating characteristics analysis, the area under the curve for MSU ranged from 0.867 to 0.947 at 15/90 mA and from 0.867 to 0.919 at 100/570 mA and that for CP from 0.659 to 0.745 and from 0.718 to 0.750, respectively. ConclusionsThis phantom study shows that single-source DECT allows detection and characterization of crystal deposits when present in soft tissue at relatively low concentrations. Further studies in patients have to prove its benefits in diagnostic imaging and treatment monitoring as well as its significance compared with dual-source CT systems.

Impact of article language in multi-language medical journals--a bibliometric analysis of self-citations and impact factor.

Background In times of globalization there is an increasing use of English in the medical literature. The aim of this study was to analyze the influence of English-language articles in multi-language medical journals on their international recognition – as measured by a lower rate of self-citations and higher impact factor (IF). Methods and Findings We analyzed publications in multi-language journals in 2008 and 2009 using the Web of Science (WoS) of Thomson Reuters (former Institute of Scientific Information) and PubMed as sources of information. The proportion of English-language articles during the period was compared with both the share of self-citations in the year 2010 and the IF with and without self-citations. Multivariable linear regression analysis was performed to analyze these factors as well as the influence of the journals‘ countries of origin and of the other language(s) used in publications besides English. We identified 168 multi-language journals that were listed in WoS as well as in PubMed and met our criteria. We found a significant positive correlation of the share of English articles in 2008 and 2009 with the IF calculated without self-citations (Pearson r=0.56, p = <0.0001), a correlation with the overall IF (Pearson r = 0.47, p = <0.0001) and with the cites to years of IF calculation (Pearson r = 0.34, p = <0.0001), and a weak negative correlation with the share of self-citations (Pearson r = -0.2, p = 0.009). The IF without self-citations also correlated with the journal‘s country of origin – North American journals had a higher IF compared to Middle and South American or European journals. Conclusion Our findings suggest that a larger share of English articles in multi-language medical journals is associated with greater international recognition. Fewer self-citations were found in multi-language journals with a greater share of original articles in English.

Comparison of MRI with radiography for detecting structural lesions of the sacroiliac joint using CT as standard of reference: results from the SIMACT study

Objective Radiographs of sacroiliac (SI) joints are used for the detection of structural damage in patients with axial spondyloarthritis (axSpA), but are often difficult to interpret. Here, we address the question how the T1-weighted MRI (T1w MRI) sequence compares with radiography for SI joints’ structural lesions using low-dose CT as the standard of reference. Methods Radiographs, T1w MRI and low-dose CT of the SI joints from 110 patients (mean age 36.1 (19–57) years, 52% males and 48% females; 53% with axSpA, 21 non-radiographic axSpA and 32% radiographic axSpA, 47% with non-SpA) referred to the rheumatologist because of unclear chronic back pain, but possible axSpA, were scored for structural lesions (erosions, sclerosis, joint space changes and an overall impression of positivity). Results Using low-dose CT as the standard of reference, T1w MRI showed markedly better sensitivity with significantly more correct imaging findings compared with radiography for erosions (79% vs 42%; p=0.002), joint space changes (75% vs 41%; p=0.002) and overall positivity (85% vs 48%; p=0.001), respectively, while there were no differences between X-rays and MRI-T1 sequence regarding specificity (>80% for all scores). Only for sclerosis, MRI-T1 was inferior to radiography (sensitivity 30% vs 70%, respectively), however, not statistically significant (p=0.663). Conclusions T1w MRI was superior to radiography in the detection of structural lesion of the SI joints in patients with axSpA. Future studies should focus on finding an agreement on the definition of MRI-T1 positivity.

Dual-energy CT virtual non-calcium technique for detection of bone marrow edema in patients with vertebral fractures: A prospective feasibility study on a single- source volume CT scanner

OBJECTIVES Dual-energy computed tomography (DECT) is a recent development for detecting bone marrow edema (BME) in patients with vertebral compression fractures. The aim of this pilot study was to determine the reliability of single-source DECT in detecting vertebral BME using magnetic resonance imaging (MRI) as standard of reference. MATERIALS AND METHODS Nine patients with radiographic thoracic or lumbar vertebral compression fractures underwent both, DECT on a 320-row single-source scanner and 1.5T MRI. Virtual non-calcium (VNC) images were reconstructed from the DECT volume datasets. Three blinded readers independently scored images for the presence of BME. Only vertebrae with loss of height in radiography (target vertebrae) were included in the analysis. A vertebra was counted as positive if two readers agreed on the presence of BME. Cohens kappa was calculated for interrater comparison. Intervertebral ratios of target and the reference vertebra were compared for CT attenuation and MR signal intensity in a reference vertebra using Spearman correlation. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. RESULTS Fourteen target vertebrae with a radiographic height loss were identified; eight of them showed BME on MRI, while DECT identified BME in 7 instances. There were no false positive virtual non-calcium images, resulting in a sensitivity of 0.88 (0.75-1.0 among all readers) and specificity of 1.0 (0.81-1.0). Interrater agreement was inferior for DECT (κ=0.63-0.89) compared to MRI (κ=0.9-1.0). Intervertebral ratio in VNC images strongly correlated with short-tau inversion recovery (r=0.87) and inversely with T1 (-0.89). SNR (0.2+/- 0.2 in VNC and 16.7+/- 7.3 in STIR) and CNR (0.2+/- 0.3 and 7.1+/- 6.3) values were inferior in VNC. CONCLUSIONS Detecting BME with single-source DECT is feasible and allows detection of vertebral compression fractures with reasonably high sensitivity and specificity. However, image quality of VNC reconstructions has to be improved to achieve better interrater agreement. Nonetheless, DECT might accelerate the diagnostic work-flow in patients with vertebral compression fractures in the future and reduce the number of additional MRI examinations.

Single source dual-energy computed tomography in the diagnosis of gout: Diagnostic reliability in comparison to digital radiography and conventional computed tomography of the feet

OBJECTIVES To investigate the diagnostic value of single-source dual-energy computed tomography (SDECT) in gouty arthritis and to compare its capability to detect urate depositions with digital radiography (DR) and conventional computed tomography (CT). METHODS Forty-four patients who underwent SDECT volume scans of the feet for suspected gouty arthritis were retrospectively analyzed. SDECT, CT (both n=44) and DR (n=36) were scored by three blinded readers for presence of osteoarthritis, erosions, and tophi. A diagnosis was made for each imaging modality. Results were compared to the clinical diagnosis using the American College of Rheumatology (ACR) classification criteria. RESULTS The patient population was divided into a gout (n=21) and control (n=23) group based on final clinical diagnosis. Osteoarthritis was evident in 15 joints using CT and 30 joints using DR (p=0.165). There were 134 erosions detected by CT compared to 38 erosions detected by DR (p<0.001). In total 119 tophi were detected by SDECT, compared to 85 tophi by CT (p=0.182) and 25 tophi by DR (p<0.001). SDECT had best diagnostic value for diagnosis of gout compared to DR and conventional CT (sensitivity and specificity for SDECT: 71.4% and 95.7%, CT: 71.4% and 91.3% and DR: 44.4% and 83.3%, respectively). For all three readers, Cohens kappa for DR and conventional CT were substantial for all scoring items and ranged from 0.75 to 0.77 and 0.72-0.76, respectively. For SDECT Cohens kappa was good to almost perfect with 0.77-0.84. CONCLUSIONS SDECT is capable to detect uric acid depositions with good sensitivity and high specificity in feet, therefore diagnostic confidence is improved. Using SDECT, inter-reader variance can be markedly reduced for the detection of gouty tophi.

OP0050 Erosion Detection on the Si-Joints - A Comparison between X-Ray, Low Dose CT and MRI Including High Resolution Sequences

Background The value of magnetic resonance imaging (MRI) in the detection of erosions on the sacroiliac joints (SI-joints) is controversial. Structural changes on the other hand are getting more and more into scientific focus. Objectives The aim of this study is a comparison between x-ray, low dose computed tomography (CT) and MRI. The presented data are preliminary results from the sacroiliac joint magnetic resonance imaging and computed tomography (SIMACT) study. Methods We investigated prospectively 30 patients with lower back pain and the suspicion of axSpA expressed by an experienced rheumatologist. All patients underwent a low dose CT (Somatom Definition Flash, Siemens, Germany) and an MRI (3.0T Magnetom Skyra, Siemens, Germany) of the SI-joints. Imaging data were compared with X-ray of the pelvis. The MRI protocol contained these sequences: T1-weighted spine echo (T1-SE), short tau inversion recovery (STIR), T1-weighted 3D volumetric interpolated breath hold examination (VIBE) high resolution sequence, all in paracoronal orientation. The grade of the disease was scored in X-ray according to the modified New York criteria and the erosions were counted by quadrant by a blinded reader. The final diagnosis made by the rheumatologist was also used for comparison. Results CT and T1-SE showed no significant differences in detecting erosions. 3D-VIBE found significantly more erosions in patients with axSpA compared to CT and T1-SE. (n=22; CT 178 erosions, T1 163, VIBE 421; average CT 5.9, T1 5.4, VIBE 14.0; p<0.001). In other diagnosis (osteoarthritis N=4, triangular hyperostosis N=3, others N=1) there were no significant differences among imaging modalities. The erosion count in 3D-VIBE correlated with the grade of sacroiliitis in X-ray (r=0.123, p=0.007). Conclusions High-resolution 3D MR sequences like 3D-VIBE are more suitable in detecting erosions on the SI-joints than conventional MRI (T1-SE) and even low dose CT. They are therefore a reasonable supplement to any MRI protocol and may improve the ability of MRI for diagnosis both in early and advanced SpA. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.2145

Cyst-like lesions in finger joints detected by conventional radiography: Comparison with 320-row multidetector computed tomography

OBJECTIVE Many rheumatologists and radiologists routinely assess conventional radiographs of the hands, and it is often unclear how to proceed if radiography reveals only cyst-like lesions (CLLs), with otherwise normal findings. The present study was undertaken to evaluate the use of 320-row multidetector computed tomography (MDCT) of the hands in the further assessment of CLLs of metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints identified on conventional radiography. METHODS MCP and PIP joints (n = 1,120 joints) of 56 consecutive patients (44 women [mean age 55 years, range 31-72 years] and 12 men [mean age 57 years, range 37-77 years]) were prospectively scored for the presence of cysts, CLLs, and erosions of the PIP and MCP joints, first on conventional radiographs, then on MDCT. Scoring was performed by 2 independent readers under blinded conditions. Intraclass correlation coefficients were calculated. RESULTS By conventional hand radiography, 13 patients (total of 260 joints assessed) were identified as having CLLs in 1 or more joints (total of 36 joints [11 PIP and 25 MCP]). By MDCT, the findings in 19 of 36 joints (53%) were diagnosed as erosions, while 7 of 36 (19%) were confirmed as true cysts, and 10 joints (28%) were normal (false positive). Among the patients with CLLs, 10 of 224 joints with no abnormality seen radiographically had erosions as seen on MDCT. Interreader agreement for erosions was 0.854 (95% confidence interval [95% CI] 0.831-0.874) by conventional hand radiography and 0.952 (95% CI 0.943-0.959) by MDCT. CONCLUSION Our results indicate that radiographic appearance of cyst-like lesions may actually represent erosions and should lead to initiation of further imaging tests.

Comparison of Clinical Examination versus Whole-body Magnetic Resonance Imaging of Enthesitis in Patients with Early Axial Spondyloarthritis during 3 Years of Continuous Etanercept Treatment

Objective. To compare clinical examination versus whole-body magnetic resonance imaging (WB-MRI) of enthesitis in patients with early axial spondyloarthritis during 3 years of continuous etanercept (ETN) treatment. Methods. Forty-one patients underwent clinical and WB-MRI examinations for enthesitis at baseline and after 2 and 3 years of treatment. Twenty-one sites were assessed in 4 anatomic regions — anterior chest wall, pelvis, knee, and foot. Results. Clinical examination at baseline detected enthesitis in 57% of the patients (85 lesions, mean 2.1 lesions, SD 2.9), most of them in the pelvis (42 lesions in 17 patients) and anterior chest wall (19 lesions in 10 patients). The proportion of patients with clinically detected enthesitis decreased to 19% at Year 2 (mean 0.5, SD 1.5) and 14% at Year 3 (mean 0.7, SD 1.8). WB-MRI detected enthesitis at baseline in 21% of patients (22 lesions, mean 0.5 lesions, SD 1.1), also most frequently in the pelvis (12 lesions) and anterior chest wall (7 lesions). MRI-positive enthesitis decreased to 13% at Year 2 (mean 0.2 lesions, SD 0.5) and 14% at Year 3 (mean 0.2 lesions, SD 0.5). There was positive correlation of clinical and MRI findings at baseline at the anterior chest wall (p = 0.001) and the pelvis (p = 0.0001). No correlation was found at the knee and foot at baseline and for all regions at followup. Conclusion. Both clinical examination and WB-MRI show a decrease in enthesitis after 2 and 3 years of ETN treatment, but correlation was limited to the pelvis and anterior chest wall at baseline.