Chronic kidney disease (CKD) is a major cause of morbidity and mortality, which affects almost 700 million people representing 9.1% of the global population [
1]. From that, approximately 15–74.7 million cases occur in children and adolescents [
2‐
5]. In comparison to adults, wherein arterial hypertension or diabetes mellitus are the main etiologies of CKD [
1,
6,
7], most pediatric cases originate from congenital disorders [
3,
8]. At present, the only available option to obtain specific information about the extent of altered kidney tissue is derived from kidney biopsy and histological analysis. This requires invasive removal of a small tissue sample, while at the same time, it only represents a small proportion of the organ as a whole [
9]. In clinical practice, the degree of renal dysfunction is determined by estimating glomerular filtration rate (GFR) from blood samples [
10,
11]. In contrast to laboratory measurements, imaging enables direct visualization and quantification of kidney tissue remodeling, inflammation, and fibrosis [
10,
12‐
14]. However, various imaging techniques are gaining momentum to objectively assess kidney structure and function [
11,
14,
15]. Advanced imaging techniques, such as magnetic resonance imaging (MRI), are expensive and challenging in the youngest patients by the need of sedation and the associated risks [
16]. Therefore, there is an unmet clinical need for novel imaging biomarkers in pediatric medicine to diagnose and monitor structural, functional, and molecular changes during CKD progression. In this regard, raster-scanning optoacoustic mesoscopy (RSOM) offers the opportunity for non-invasive, agent-free tissue imaging by the photo-/optoacoustic effect [
17,
18]. Using a pulsed laser light source to excite tissue chromophores such as hemoglobin, RSOM detects acoustic pressure waves generated from thermoelastic expansion of these molecules [
19,
20]. Imaging with RSOM has currently gained interest for imaging human skin diseases [
21]. The purpose of this pilot study was to visualize and quantify changes in renal vascular morphology by RSOM in healthy mice and mice with renal injury [
22].