Computed tomography parameters can be used as predictive markers for the improvement of renal function in patients with retroperitoneal fibrosis.

OBJECTIVES: To discover the relationship between computed tomography (CT) parameters of retroperitoneal soft tissue of untreated retroperitoneal fibrosis patients and the variation of renal function after treatment.

METHODS: Data were collected retrospectively from 42 patients with established diagnosis of retroperitoneal fibrosis, at the Department of Rheumatology in Peking University First Hospital from May 2009 to April 2015. The demographic information, clinical characteristics, laboratory data, treatment and general therapeutic response were collected. The CT parameters such as radial lines, Hounsfield unit values, radiographic classification at baseline before the initiation of therapy were measured. Then the correlations between baseline CT parameters and clinical data were analysed.

RESULTS: The Hounsfield unit values of venous phase and delayed phase at baseline were negatively correlated with the change of estimated glomerular filtration rate (eGFR) at the 12th month after the initiation of medications. The baseline transverse diameters of the retroperitoneal soft tissue were larger in the group of eGFR <60 ml/min/1.73 m² compared with the group of eGFR ≥ 60 ml/min/1.73 m² at the 12th month, while the vertical diameters and maximum cross-section thickness were not. The baseline transverse diameters were also significantly correlated with the duration of intubation.

CONCLUSIONS: The baseline Hounsfield unit values and baseline transverse diameters of soft tissue of untreated retroperitoneal fibrosis patients may be used to predict the renal function after 12 months of therapy.