Initial Experience of Using Dual-Energy CT with an Iodine Overlay Image for Hand Psoriatic Arthritis: Comparison Study with Contrast-enhanced MR Imaging

Abstract

Purpose To determine the feasibility of dual-energy (DE) computed tomography (CT) with an iodine overlay image (IOI) for evaluation of psoriatic arthritis in the hand. Materials and Methods Approval from the institutional ethics committee and written informed consent from all patients were obtained. This prospective study included 16 patients who had psoriasis with finger joint symptoms from January 2015 to January 2016. Contrast material-enhanced (CE) DE CT and 1.5-T CE magnetic resonance (MR) imaging were performed within 1 month of each other. DE CT was performed with a tube voltage of 80 kV and 140 kV with use of a 0.4-mm tin filter. Images acquired with both modalities were evaluated by two radiologists independently by using a semiquantitative scoring system. Interreader agreement was calculated for each modality: Weighted κ values were calculated for synovitis, flexor tenosynovitis, and extensor peritendonitis, and κ values were calculated for periarticular inflammation. With consensus scores and CE MR images as the reference, the sensitivity and specificity of IOI DE CT for inflammatory lesions were calculated. Statistical analysis of discordant readings was performed by using the McNemar test. Results Interreader agreement for inflammatory lesions was excellent or good (weighted κ = 0.83 and κ = 0.75 in IOI DE CT; weighted κ = 0.81 and κ = 0.87 in CE MR imaging). The sensitivity and specificity of IOI DE CT were 0.78 and 0.87, respectively. Total agreement was 86.3%; however, there were significantly more lesions detected with IOI DE CT than with CE MR imaging alone (134 vs 20 lesions in 1120 evaluated items; P < .001). Sixty-nine percent of the abnormalities detected with IOI DE CT alone were located in distal interphalangeal joints. Conclusion IOI DE CT is a new imaging modality that may be useful for evaluating psoriatic arthritis in the hand, particularly in the detection of inflammatory lesions in small joints, and may be more useful than CE MR imaging, within the limitation that there is no histopathologic reference. RSNA, 2017.

Quantitative analysis of therapeutic response in psoriatic arthritis of digital joints with Dual-energy CT iodine maps

“…With the rapid development of treatment options, including biologic therapies, it is preferable to treat enthesitis and synovitis before bone erosion and joint destructions occur 21,22 . Although PsADECTS is a useful tool in evaluating the severity of PsA, and is shown to be as useful or may be superior in assessment of inflammation of small joint as MRI 17 , there is a degree of subjective element in the scoring process and also the scoring of each joint is time consuming. Consequently, developing a tool to assess the severity and treatment response in a more objective and efficient manner, before irreversible structural changes occur to lessen its unsightly and disabling progression, is desirable.…”

“…All images were evaluated by two qualified radiologists (R.K. and T.F., with 4 and 8 years of experience in interpreting musculoskeletal CT images, respectively) independently, while blinded to clinical data and other images. The symptomatic and non-symptomatic joints were scored according to PsADECTS 17 . PsADECTS was scored out of 10: synovitis, flexor tenosynovitis, extensor peritendonitis (each scored out of 3) and periarticular inflammation (scored 1 if present).…”

“…Dual-energy CT (DECT) iodine mapping was first introduced into the clinical setting in 2005, which enabled quantitative assessment of iodine contrast enhancement and the creation of iodine maps, by acquiring two different sets of data from two different energy levels of X-rays 15 . DECT iodine mapping is highly sensitive in depicting inflammation around the joints in PsA 16 and can be used for semiquantitative assessment by using a modified version of PsAMRIS 17 , a recently validated method that assesses PsA changes on MRI 12,13 . In this study we have defined this scoring system as the PsA DECT Scoring System (PsADECTS), which is shown to be as useful or may be superior as the MRI in assessing inflammation of small joints 17 .…”

Usefulness of dual‐energy computed tomography for the evaluation of psoriatic arthritis accompanied by knee osteoarthritis

“…DE-CT is a new imaging modality and is potentially useful for evaluating the presence and activity of inflammation in patients with PsA because of its high spatial resolution and image reconstruction capability compared with MRI. 4 In addition, the effect of treatment on the degree of inflammation can be evaluated on DE-CT images. It is important for clinicians to consider that PsA, OA, gout and other diseases can cause joint pain in psoriatic patients, and imaging modalities such as MRI, ultrasound or DE-CT in addition to X ray should be used to achieve an accurate diagnosis.…”

Usefulness of dual‐energy computed tomography for the evaluation of early‐stage psoriatic arthritis only accompanied by nail psoriasis

“…Dual-energy CT appears to be more useful than magnetic resonance imaging to elucidate the presence of finger joint inflammation of PsA with high spatial resolution. 3 Although ultrasonography may also be useful, 4 individual skillful techniques are obviously required. DE-CT depicted rapid improvement of enthesitis after treatment with adalimumab, followed by gradual and delayed improvement of nail psoriasis, as expected.…”