Tocilizumab effects in COVID-19 pneumonia: role of CT texture analysis in quantitative assessment of response to therapy

• DOI: 10.1007/s11547-021-01371-7
• Publication Date: 2021-06-05T08:03:26Z
• Authors: Giorgio Maria Masci; Franco Iafrate; Fabio Ciccarelli; Giacomo Pambianchi; Valeria Panebianco; Patrizia Pasculli; Maria Rosa Ciardi; Claudio Maria Mas...; Paolo Ricci; Carlo Catalano; Marco Francone
• Keywords: Adult; Aged, 80 and over; Male; Chest Radiology; COVID-19; Kaplan-Meier Estimate; Middle Aged; Antibodies, Monoclonal, Humanized; Receptors, Interleukin-6; Severity of Illness Index; Survival Analysis; COVID-19; computed tomography; pneumonia; tocilizumab; treatment; COVID-19 Drug Treatment; 3. Good health; 03 medical and health sciences; Treatment Outcome; 0302 clinical medicine; Humans; Female; Tomography, X-Ray Computed; Lung; Aged; Retrospective Studies

To evaluate CT and laboratory changes in COVID-19 patients treated with tocilizumab, compared to a control group, throughout a combined semiquantitative and texture analysis of images.From March 11 to April 20, 2020, 57 SARS-CoV-2 positive patients were retrospectively compared: group T (n = 30) receiving tocilizumab and group non-T (n = 27) undergoing only antivirals/antimalarials. Chest-CT and laboratory findings were analyzed before and after treatment. CT evaluation included both semiquantitative scoring and texture analysis of all parenchymal lesions. Survival and recovery analyses were also provided with Kaplan-Meier method.In group T, no significant differences were found for CT score after treatment, while several texture features significantly changed, including mean attenuation (p < 0.0001), skewness (p < 0.0001), entropy (p = 0.0146) and higher-order parameters, suggesting considerable fading of parenchymal lesions. PaO2/FiO2 mean value significantly increased after treatment, from 240 ± 93 to 363 ± 107 (p = 0.0003), with parallel decrease in inflammatory biomarkers (CRP, D-dimer and LDH). In group non-T, CT scoring, texture and laboratory parameters showed significant worsening at follow-up. Findings were clinically associated with opposite trends between two groups, with reduction of severe cases in group T (from 21/30 to 5/30; p < 0.0001) as compared to a significant worsening in group non-T (severe cases increasing from 6/27 to 14/27; p = 0.0473). Probability of discharge was significantly higher in group T (p < 0.0001), as well as survival rate, although not statistically significant.Our results suggest the potential role of CT texture analysis for assessing response to treatment in COVID-19 pneumonia, using Tocilizumab, as compared to semiquantitative evaluation, providing insight into the intrinsic parenchymal changes.