18F-fluorodeoxyglucose positron emission tomography-based evaluation of systemic and vascular inflammation and assessment of the effect of systemic treatment on inflammation in patients with moderate-to-severe psoriasis: A randomized placebo-controlled pilot study

Abstract

Background: Psoriasis is a systemic inflammatory disorder associated with an increased risk of cardiovascular disease.

Objective: To evaluate the utility of [^[18]F]-fluorodeoxyglucose positron emission tomography/computed tomography in identifying vascular and systemic inflammation in psoriasis patients with moderate-to-severe disease and to analyze its usefulness in assessing the effect of systemic treatment.

Methods: This was a randomized, double-blind pilot study conducted in a tertiary care center. Baseline standardized uptake value score was estimated by¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with moderate-to-severe psoriasis and compared with historical controls. Patients were then randomized using computer-generated randomization list into methotrexate or placebo (with or without pioglitazone) groups.¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography was repeated at 12 weeks and composite standardized uptake value score determined. The correlation between Psoriasis Activity and Severity Index and SUVmax was assessed.

Results: A total of 16 patients were randomized to different treatment groups. Significant increase in mean SUVmax was observed in the ascending aorta in psoriasis patients as compared to historical controls (2.03 ± 0.53 vs 1.51 ± 0.36, P < 0.03). There was no difference in composite standardized uptake value score after 12 weeks of treatment in any of the treatment groups (P = 0.82), although an improvement in Psoriasis Activity and Severity Index score in the methotrexate arm was observed. No correlation was found between mean SUVmax and Psoriasis Activity and Severity Index scores in various aortic segments (r = 0.3-0.7).

Limitations: Small sample size, short follow-up, historical controls, exclusion of patients with comorbid conditions and lack of surrogate markers of systemic inflammation.

Conclusion: ¹⁸F-fluorodeoxyglucose positron emission tomography imaging showed higher vascular inflammation in ascending aorta of psoriasis patients as compared to historical controls. Systemic treatment with methotrexate and pioglitazone did not influence the vascular inflammation in the short term.

Keywords: Atherosclerosis; fluorodeoxyglucose positron emission tomography/computed tomography; maximum standardized uptake value; psoriasis; systemic inflammation.