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

Abstract

the aim of this study was to investigate the feasibility of quantitative assessment of the therapeutic response in psoriatic arthritis (psA) by measuring iodine uptake using a Dual-energy ct (Dect) iodine map. The study included 74 symptomatic and 74 matching non-symptomatic joints of 26 consecutive psA patients who underwent two contrast enhanced Dects of the hand or foot, pre and post medical interventions. Symptomatic and matched non-symptomatic control joints were scored with the psA Dect Scoring System (psADectS), which was derived by modifying the psA MRi Scoring System (PsAMRIS), a recently validated scoring system that assesses PsA changes on MRI. Quantified iodine uptake measured using the DECT iodine map was compared to the PsADECTS score. Efficacy of PsA treatment was confirmed by the improved clinical findings. Both PsADECTS and iodine uptake also showed significant improvement after treatment (Wilcoxon signed-rank test: z = 7.38, p < 0.005; z = 6.20, p < 0.005, respectively). The treatment effects of PsADECTS score and iodine uptake showed a good correlation with each other (Spearman's ρ = 0.58 p < 0.005). Inter-reader agreement for psADectS score and iodine uptake were either moderate or good. in conclusion, our study showed that the Dect iodine map is a valid tool for quantitative assessment of the therapeutic response of psA.

Relationship between iodine‐enhanced dual energy‐computed tomographic findings and ultrasonographic findings for psoriatic arthritis

“…Recently, we reported that iodine uptake correlated with a scoring system for the local inflammatory lesions as well as scores of visual analog scale for pain in PsA 16 . However, iodine uptake did not correlate with PACE scores in our study.…”

“…The presence or absence of synovitis, extensor peritendinitis, and periarticular inflammation was confirmed on iodine‐enhanced DECT images. These findings constitute the PsA scoring system, except for flexor tenosynovitis 16 . The estimated amount of iodine uptake was calculated as the average iodine concentration per pixel multiplied by pixel numbers (unitless) for ROI at the level at which the joint was the most severely affected in view of synovitis, extensor peritendinitis, and periarticular inflammation on the sagittal plane of the finger or toe.…”

“…These findings constitute the PsA scoring system, except for flexor tenosynovitis. 16 The estimated amount of iodine uptake was calculated as the average iodine concentration per pixel multiplied by pixel numbers (unitless) for ROI at the level at which the joint was the most severely affected in view of synovitis, extensor peritendinitis, and periarticular inflammation on the sagittal plane of the finger or toe. The bone area was excluded from ROI because bone interferes with iodine calculations due to its high Xray attenuation.…”

Virtual Monoenergetic CT Imaging via Deep Learning

“…Material decomposition provides quantitative information about tissue composition to distinguish soft tissues, calcium, and iodine for important clinical applications. 10 , 11 , 12 Currently, material decomposition is widely applied for tissue characterization, kidney stone analysis, vascular mapping, nodule classification, and proton therapy planning. 13 , 14 , 15 , 16 …”

“…Material decomposition provides quantitative information about tissue composition to distinguish soft tissues, calcium, and iodine for important clinical applications. [10][11][12] Currently, material decomposition is widely applied for tissue characterization, kidney stone analysis, vascular mapping, nodule classification, and proton therapy planning. [13][14][15][16] A method to approximate the energy-dependent information using only a single-spectrum scan would enable improved clinical diagnosis of patients for whom DECT scans are not available.…”