Addition of CT to Improve the Diagnostic Confidence for the Detection of Sacroiliac Joint Erosions in Patients with Equivocal MRI Findings

Purpose To determine if CT can improve the diagnostic confidence for the detection of sacroiliac joint (SIJ) erosions in patients with equivocal MRI findings. Methods A retrospective analysis of adult patients who had an SIJ MRI and a subsequent SIJ CT within 12 months was conducted. Using a 5-point Likert scale, two reviewers evaluated the de-identified MRI and CT images in randomized order and in separate sessions to answer the question: “Does the patient have SIJ erosions?”. A Fisher’s exact test was used to analyze the difference in diagnostic confidence, and intraclass correlation coefficient (ICC) was used to determine interrater reliability. Results 54 patients were included in the analysis (average age, 43.9 years). The average time interval between initial SIJ MRI and subsequent CT was 14.4 weeks (range, 5.6–50.3 weeks). CT resulted in significantly more cases with definitive diagnostic confidence than cases with probable or equivocal confidence compared to MRI ( P < .001). Amongst cases with equivocal findings on MRI, 73.2% of cases had definitive diagnoses on CT. There was moderate interrater agreement for MRI, with an ICC of .490 [95% CI, .258–.669], and excellent agreement for CT, with an ICC of .832 [95% CI, .728–.899]. Conclusion Overall, CT led to significantly increased diagnostic confidence and higher interrater reliability for the detection of SIJ erosions compared to MRI. Judicious use of CT may be useful in detecting SIJ erosions in patients with equivocal MRI findings.

Serum Dickkopf-1 as a potential prognostic marker in patients with rheumatoid arthritis

Background Rheumatoid arthritis (RA) is a disease of an autoimmune nature that involves all types of joints structures and manifested by chronic joints inflammations and thus their erosions and damage. Dickkopf-1 (DKK-1) is a molecule that has an inhibitory regulation of wingless/integrated genes (Wnt) pathway and has a major role in models of animals with arthritis or joint destruction. Increased DKK-1 levels are implicated in higher resorption of the bone in cases of rheumatoid arthritis and thus with higher probability for joint deformities, while low levels associated with formation of new bone by osteoblasts, we aimed to study the prognostic role of circulating Dickkopf-1 in rheumatoid arthritis. Results The present study revealed that the DKK-1 levels were significantly increased in RA patients in relation to the control group (P=0.001). We found a significant positive correlation between DKK-1 level and ESR (P=0.001), Disease Activity Score (DAS 28) (P=0.001), the disease duration (P=0.001), and the presence of bone erosions in plain X-ray of hands (P =0.001). Moreover, we revealed that, at cutoff value 2150, the DKK-1 in RA has 90% sensitivity and 85% specificity. Conclusions DKK-l serum level can be used as a potential prognostic biomarker for monitoring of joint erosions and destruction in RA patients. Furthermore, it could be a possible target molecule in the future therapy to control the process of joint destruction.

Psoriatic Arthritis

Chapter 33 discusses psoriatic arthritis, which is a seronegative spondyloarthropathy (SpA) affecting the peripheral and axial skeleton that may precede skin manifestations. Psoriatic arthritis is a challenging diagnosis because it often initially presents without psoriasis, lacks specific serologic markers, and resembles osteoarthritis and other inflammatory arthropathies. It is associated with joint erosions, destruction, and ankylosis often involving the distal interphalangeal (DIP) joints. Radiography is the primary imaging modality for initial diagnosis and monitoring disease progression and treatment efficacy. Skin and nail involvement and characteristic imaging findings are key criteria for diagnosis. MRI and US of symptomatic joints and/or MRI of the sacroiliac (SI) joints may be useful in clinically challenging cases.