IgA antibodies against CD74 are associated with structural damage in the axial skeleton in patients with axial spondyloarthritis

OBJECTIVES

To study the association between the presence of antibodies against CD74 and structural damage in the sacroiliac joints and spine in patients with axial spondyloarthritis (axSpA).

METHODS

Antibodies against CD74 were measured in the sera of patients with axSpA from 2 cohorts: 1. An observational cohort from Damp in Northern Germany and 2. from a clinical trial (ENRADAS), in which the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) had been evaluated by two readers blinded to the time point at baseline and two years later. The presence of antibodies against CD74 was correlated with the presence and grade of radiographic sacroiliitis in the observational cohort, and with baseline mSASSS in the ENRADAS cohort.

RESULTS

The sensitivity of IgA anti-CD74 antibodies for axSpA was 50% in the Damp cohort and 42% in ENRADAS. The presence of IgA antibodies against CD74 was associated with a higher grade of sacroiliitis (observational cohort) and a higher baseline mSASSS in the ENRADAS cohort.

CONCLUSIONS

IgA antibodies against CD74 are not only markers of AS, but are associated with structural damage development in the sacroiliac joints and in the spine.

Single-source dual-energy computed tomography for the detection of bone marrow lesions: impact of iterative reconstruction and algorithms

PURPOSE

To compare the diagnostic performance of different reconstruction algorithms of single-source dual-energy computed tomography (DECT) for the detection of bone marrow lesions (BML) in patients with vertebral compression fracture using MRI as the standard of reference.

MATERIAL AND METHODS

Seventeen patients with an age over 50 who underwent single-source DECT of the spine were included. The raw data (RD) were reconstructed using filtered back-projection (FBP) and iterative reconstruction (IR) with three iteration levels (IR1-IR3). Bone marrow images were generated using a three-material decomposition (3MD) and a two-material decomposition (2MD) algorithm and an RD-based approach. Three blinded readers scored the images for image quality and the presence of bone marrow lesions (BML). Only vertebrae with height loss were included. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The different reconstructions were compared using Dunn's multiple comparison test.

RESULTS

Thirty-nine vertebrae were included. IR(1-3) showed superior sensitivity (87.5%) compared to FBP (75%) using 3MD but was comparable to RD (83.3%). All 2MD images were inferior (sensitivity < 38%). The image quality score was significantly higher for 3MD-IR(1-3) compared to 3MD-FBP (p < 0.0001) and all 2MD data sets (p < 0.03). This pattern was also supported by the SNR and CNR measurements. RD showed no significant improvement compared to IR.

CONCLUSION

The image quality of bone marrow images acquired with DECT can be improved by using IR compared with FBP. RD-based reconstruction does not offer significant improvement over image data-based reconstruction. 2MD algorithms are not suitable for BML detection.

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. Cohen's 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.

Relationship between active inflammatory lesions in the spine and sacroiliac joints and new development of chronic lesions on whole-body MRI in early axial spondyloarthritis: results of the ESTHER trial at week 48

AIM

To investigate the relationship between active inflammatory lesions on whole-body MRI (wb-MRI) and new development of chronic lesions on T1 MRI in patients with early axial spondyloarthritis (SpA) treated either with etanercept (ETA) or sulfasalazine (SSZ).

METHODS

Wb-MRIs of 65 patients treated either with ETA (n=35) or SSZ (n=30) over 1 year were scored for active inflammation, fatty lesions, erosions and ankylosis in the 23 vertebral units (VUs) of the spine and in the sacroiliac joints (SI joints). Scoring was performed by two blinded radiologists.

RESULTS

If there was no previous inflammation in the bone no new fatty lesions occurred in SI joint quadrants and only a few (0.6%) in spine VUs. There was a significant relationship between disappearance of inflammation and the appearance of fatty lesions: if baseline inflammation resolved fatty lesions occurred in 10.5% of SI joint quadrants and 17.9% of VUs. If inflammation did not resolve over 1 year, fatty lesions occurred less frequently: 2.4% (SI joint quadrants) and 7.2% (VUs). There was a significantly higher increase of the mean fatty lesion score between baseline and week 48 in the ETA (4.0 vs 4.8 for the SI joints and 1.9 vs 2.7 for the spine) compared to the SSZ (3.0 vs 3.2 for the SI joints and 1.1 vs 1.2 for the spine, respectively) group (p=0.001 and p=0.020 for the differences). No significant changes in the erosion or ankylosis score were observed in any of the two groups during this time.

CONCLUSIONS

These data indicate that there is a close interaction between inflammation, tumour necrosis factor blockade and the development of fatty lesions in subchondral bone marrow of patients with axial SpA.

Contrast-enhanced ultrasound in monitoring the efficacy of a bradykinin receptor 2 antagonist in painful knee osteoarthritis compared with MRI

OBJECTIVES

To evaluate contrast-enhanced ultrasound (CE-US) as a monitoring tool to assess hypervascularisation of synovial processes in knee osteoarthritis (OA) treated with intra-articular injections of the bradykinin-receptor 2 antagonist icatibant compared to contrast-enhanced magnetic resonance imaging (CE-MRI).

PATIENTS AND METHODS

In a randomised, double-blind, placebo-controlled trial, 41 patients with painful knee OA underwent US (12.5 MHz for B-mode and 3-8 MHz for CE-US), and 36 of the patients underwent additional MRI (0.2T) at baseline and after 3 injections of the study drug (after a mean of 22.2 days). A total of 15 patients received placebo (group A), 12 patients 500 microg icatibant (group B) and 14 patients 2000 microg icatibant (group C). Pain and the synovial process (B-mode, power Doppler US (PD-US), CE-US, CE-MRI) were assessed at both time points.

RESULTS

At baseline, the placebo group showed more activity in terms of effusion in the superior and lateral recess in ultrasound as well as in PD-US in the lateral recess. Pain improved significantly in all subgroups. Effect sizes were 0.43 (pain at rest) and 0.52 (pain during activity) in group B vs 0.48 and 1.11 in group C. There was no change of US and MRI parameters. We found moderate to good correlation (r) and kappa values (kappa) for effusion in the superior recess (r = 0.591, k = 0.453), effusion in the lateral recess (r = 0.304, k = 0.440) and contrast enhancement (r = 0.601, k = 0.242) between US and MRI.

CONCLUSIONS

Our results show that CE-US and CE-MRI have good agreement in assessing inflammatory changes in knee OA. For the 41 patients with OA, an analgesic effect of icatibant could clearly be shown, especially for pain during activity in the high dose icatibant group. However, we could not find an anti-inflammatory effect of icatibant by CE-US compared to CE-MRI.

[Imaging in ankylosing spondylitis]

In addition to the typical clinical symptoms, conventional x-rays and magnetic resonance imaging (MRI) are important for the diagnosis and management of ankylosing spondylitis (AS). While radiography is mainly useful for detecting chronic structural changes, MRI is, in addition, able to detect active inflammation. The detection of structural changes in the sacroiliac joints and, in part, the spine, remains the gold standard for the diagnosis of AS. The detection of active sacroiliitis or spondylitis in early disease stages is only possible using MR techniques such as STIR and T1 post-gadolinium sequences. Lateral radiographs of the spine are useful for detecting shiny corners and the characteristic syndesmophytes and ankylosis. The modified Stoke Anklyosing Spondylitis Spine Score (SASSS) is the best scoring method for quantifying such changes, allthough only the cervical and the lumber spine are evaluated with this method. MRI changes can also be quantified. New scoring methods are sensitive to change only 3 months after initiation of therapy with anti-TNF agents.

[Ankylosing spondylitis--current state of imaging including scoring methods]

Conventional radiography and magnetic resonance imaging (MRI) are currently the most widely used imaging methods for the initial diagnostic evaluation and follow-up of patients with ankylosing spondylitis (AS). Scintigraphy, computed tomography (CT), and positron emission tomography (PET) only play minor roles, although some are being further developed. AS is characterized by inflammatory changes to the sacroiliac joints (SIJs) and spine, as well as asymmetrical arthritis of the peripheral joints and joints near the trunk. The diagnosis of AS is based on clinical parameters and the presence of chronic inflammatory changes to the SIJs on conventional radiographs. Typical radiographic changes also involve the spine. MRI depicts not only chronic changes, but also active inflammatory lesions, which are important for the diagnosis of early disease and precursors of AS. The scoring system of choice for quantifying spinal changes depicted by conventional radiography is the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). MRI allows the quantitative evaluation of changes involving the SIJs and the spine. Various MRI scoring systems have been proposed to quantify these changes, but they require further validation. This review article presents the imaging modalities used in AS patients, typical findings, and relevant methods of analysis. The most recent developments are discussed.

Evaluation of a wavelet-based computer-assisted detection system for identifying microcalcifications in digital full-field mammography

PURPOSE

To evaluate a new wavelet-based computer-assisted detection (CAD) system for detecting and enhancing microcalcifications.

MATERIAL AND METHODS

A total of 280 mammograms acquired by full-field digital mammography (Senographe 2000D; G.E. Medical Systems Milwaukee, Wisc., USA) were analyzed with and without a new wavelet-based CAD system for detecting and enhancing microcalcifications. The mammograms comprised roughly equal numbers of cases from each of the BIRADS (Breast Imaging, Reporting and Data System, according to the American College of Roentgenology) categories 1-5. Histologic confirmation was available for all of the 180 cases assigned BIRADS categories 3-5. Four readers interpreted all 280 images for suspicious microcalcifications using a scale of 1-5. The readers alternately assessed 5 images with and 5 without CAD. In a second reading immediately following the first, the readers had to reassess the 280 mammograms. The images that had already been interpreted without CAD were now presented with CAD and vice versa. The images were interpreted as soft copies on a diagnostic mammography workstation (Image Diagnost GmbH, Neufahrn/Munich, Germany). All images interpreted with CAD were presented with enhancement of microcalcifications by wavelet algorithms and prompting of microcalcifications. ROC (receiver operating characteristic) analyses were performed, and image interpretation time with and without CAD was measured.

RESULTS

The overall time for interpretation required by all 4 readers together was 483 min with CAD compared to 580 min without CAD. ROC analysis revealed no significant advantage of CAD for the individual readers. Readers 3 (0.811/0.817) and 4 (0.799/0.843) had a slightly improved AUC (area under the curve) with CAD. Readers 1 and 2 had a slightly lower AUC with CAD (0.832 versus 0.861 and 0.818 versus 0.849).

CONCLUSION

The CAD system significantly (P<0.05, t test) speeded up image interpretation with respect to the identification of microcalcifications, while the diagnostic quality remained almost identical under the study conditions.

Impact of a clinical pharmacokinetic service on patients treated with aminoglycosides: a cost-benefit analysis

In a prospective, randomized study, 75 adults receiving aminoglycosides were followed by a clinical pharmacokinetic service and 70 followed as controls. The two groups were similar in age, gender, height, and APACHE II score. A cost-to-charge ratio was used to derive direct costs of hospitalization and calculate cost-benefit. Excluded from this comparison were patients with incomplete acceptance of pharmacokinetic service recommendations and patients followed by other clinical pharmacists. Pharmacokinetic service patients had shorter hospitalizations (322.67 +/- 270.28 h; controls 442.89 +/- 536.81, p = 0.087) and febrile periods (50.05 +/- 79.38 h; controls 92.23 +/- 122.50, p less than 0.05). More pharmacokinetic service patients had adequate peak levels. Pharmacokinetic service direct costs were lower ($7,102.56 +/- 9,898.19; controls $13,758.64 +/- 22,874.31, p less than 0.05). Calculated direct cost of the service was $85.00/patient. Annual savings for 500 patients is $2,220,540.00.