Power and spectral Doppler ultrasound in suspected active sacroiliitis: a comparison with magnetic resonance imaging as gold standard

How to inject sacroiliac joints with ultrasound guidance: a pictorial essay

Active sacroiliitis and sacroiliac joint dysfunction represent a common cause of low back pain in the population and are cause of patients' quality of life reduction and disability worldwide. The use of musculoskeletal ultrasound allows to easily identify the sacroiliac joints and to study every pathological condition affecting its most dorsal part; moreover, musculoskeletal ultrasound allows to guide highly effective injective procedures aimed at improving patients' symptoms and enhance their well-being. This paper aims to briefly explain for the musculoskeletal sonographer the anatomy and biomechanics of the sacroiliac joints, the correct ultrasound scanning method for their visualization and the most appropriate ultrasound guided injection technique to help dealing with the diagnostic and management of sacroiliac joint pain in the everyday scenario.

Novel insights into the anatomy and histopathology of the sacroiliac joint and correlations with imaging signs of sacroiliitis in case of axial spondyloarthritis

For a better understanding of the pathophysiology of spondyloarthropathy (SpA), a detailed anatomical description of the sacroiliac joint is required because sacroiliitis is the earliest and most common sign of SpA and an essential feature for the diagnosis of ankylosing spondylitis. Beyond the anatomy, the histopathology of sacroiliac entheses and immunological mechanisms involved in sacroiliitis are crucial for a better understanding of disease causation. In this narrative review, we discuss the core anatomical, histological, and immunohistological observations involved in the development of sacroiliitis, focusing particularly on imaging-based information associated with sacroiliitis. Finally, we try to answer the question of whether at the sacroiliac joint, enthesitis precedes synovitis and subchondral bone changes in SpA.

Doppler and Spectral Ultrasound of Sacroiliac Joints in Pediatric Patients with Suspected Juvenile Spondyloarthritis

Background: Power Doppler ultrasound (PDUS) with spectral wave analysis (SWA) has been compared with magnetic resonance imaging (MRI) in documenting active sacroiliitis in early spondyloarthritis (SpA) but, to date, PDUS/SWA has not been yet applied to the study of sacroiliac joints (SIJs) in children. Methods: A group of 20 children (13 F/7 M, mean age 14.2 y) with suspected juvenile SpA (jSpA) underwent PDUS/SWA and, subsequently, MRI of the SIJs. SIJs PDUS scoring and resistance index (RI) of the SIJs flows were recorded. The accuracy of PDUS/SWA for the diagnosis of active sacroiliitis was evaluated, with MRI as the gold standard. Results: PDUS signals were detected in 19 patients and 30 SIJs. Bone marrow edema (BME) lesions on MRI were detected in 12 patients (diagnosed as jSpA) and 22 SIJs. PDUS scoring on SIJs were higher in patients with a final diagnosis of jSpA (p = 0.003). On SWA, the mean RIs in patients with or without final diagnosis of active sacroiliitis were, respectively, 0.604 and 0.767 (p = 0.005) at joint level. A RI < 0.55 and PDUS > 1 showed the higher specificity for sacroiliitis (AUROC curve 0.854 for PDUS and 0.920 for RI). SIJs PDUS/SWA showed an overall concordance of 82.35%, with substantial agreement (k = 0.627) with MRI on the diagnosis of sacroiliitis. Conclusions: In children with sacroiliitis, PDUS demonstrates a rich vascularization into SIJs and low RIs (<0.55) have high specificity for this condition. SIJs PDUS/SWA could be useful as a screening method in children with suspected jSpA.

Diagnostic performance of DIXON sequences on low-field scanner for the evaluation of knee joint pathology

BACKGROUND AND AIM

Recently, there has been a growing interest in the use of Dixon sequence for knee MRI in order to save time spent on the scanner, and improving diagnostic utility. Our purpose was to compare the diagnostic performance of Dixon sequence on low-field MRI with the proton-density sequence on high-field MRI.

METHODS

This prospective study included 40 patients who underwent 0.25T knee MRI, using the routine protocol with the addition of a sagittal 4-point Dixon sequence (SPED), and an additional sequence on 1.5T scanner, consisting in a fat-suppressed proton-density fast-spin-echo (FS PD-FSE). Two radiologists independently examined the images, evaluating the anatomic identification score and diagnostic performances of the two sequences. Interreader agreement was evaluated using an intraclass correlation coefficient (ICC).

RESULTS

Final population counted 34 patients (36 knee MR images) with a mean age of 52.9 years (range, 18-75 years). Interreader agreement was very high except for cartilage injuries at medial femoral condyle and medial tibial plateau (ICC SPED: 0.757, ICC FS PD-FSE: 0.746), even if not statistically significant. There were no significant differences in mean signal-to-noise ratio (SNR), artifacts presence and diagnostic confidence between SPED and PD-FS sequence.

CONCLUSIONS

Dixon sequences on low-field scanner have a comparable diagnostic accuracy to PD-FS sequence obtained on a high field scanner for knee MR imaging. (www.actabiomedica.it).

Inflammatory Bowel Diseases and Coexisting Spondyloarthritis: A Neglected and too Often Under-Reported Association by Radiologists. A Multicenter Study by Italian Research Group of Imaging in Rheumatology

Purpose: The purpose of this study was to evaluate the prevalence and the underreporting rate of sacroiliitis (SI) in a large cohort of patients with biopsy-proved Crohn’s disease (CD) who underwent magnetic resonance enterography (MRE) or computed tomography enterography (CTE). Materials and Methods: Patients with CD were recruited from eight Italian health centers in the period from January 2013 to December 2017. Disease activity was recorded according to the CD activity index (CDAI). The scans were read by two blinded readers who defined the presence of SI according to Assessment of SpondyloArthritis International Society (ASAS) classifications and European League Against Rheumatism (EULAR) recommendations. Moreover, SI was scored using a simplified Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system. Results: Interobserver agreement in diagnosing SI on imaging was good (K = 0.72–0.83). SI was diagnosed in 129 (14.4%, 54 men, 75 women) out of 894 patients; however, sacroiliac joint (SIJ) abnormalities were not mentioned in the radiological reports of 112 patients (86%). Fifty (38.7%) out of 129 patients also underwent a subsequent SIJ evaluation through a dedicated MRI protocol to confirm SI. SI was found in a higher percentage of patients with “active” than “inactive” CD (18% vs. 4%). Conclusion: This study confirms the feasibility of CTE and MRE for the screening of SI in CD patients; however, it also underlines the remarkable problem concerning the underreporting of this entity in radiological practice.