Prevalence and risk factors of perirenal hyperintensities on T2-weighted MR imaging

To assess the prevalence and severity of perirenal hyperintensities (PRHs) on T2-weighted magnetic resonance imaging (MRI) and their risk factors in the general population.

1752 participants (910 women, 842 men, median age: 52 years) of the Study of Health in Pomerania were included. A visual classification system was established to assess the severity of PRHs (stage 0: no PRHs visible to stage 3: extensive PRHs visible). The MRI-derived thickness of the perirenal and posterior pararenal space and additional risk factors were determined and associated with PRH stages.

The overall prevalence of PRHs was 40.7% and was higher in men than in women. PRHs were more common around the left compared to the right kidney (p < 0.001). On both sides, the presence of PRHs was associated with age (p < 0.001). Multivariable-adjusted regression models revealed male sex (OR = 13.2, 95%CI 9.7; 17.9, p < 0.001), older age (OR = 1.1, 95%CI 1.1; 1.1, p < 0.001), higher body mass index (BMI; OR = 1.1, 95%CI 1.0; 1.1, p < 0.001), current smoking status (OR = 1.9, 95%CI 1.4; 2.6, p < 0.001), and greater thickness of the posterior pararenal space (OR = 1.2, 95%CI 1.2; 1.2, p < 0.001) as independent significant risk factors of left-sided PRHs. The same risk factors were confirmed for right PRHs. Glomerular filtration rate was not associated with PRHs on either sides (OR = 1.00, 95%CI 1.0;1.0, p > 0.05).

PRHs are common in the general population, with a higher prevalence in men, elderly individuals, and around the left kidney. Furthermore, BMI, posterior pararenal space thickness, and current smoking, but not renal function itself, are associated with the presence of PRHs.