Bridging the macro to micro resolution gap with angiographic optical coherence tomography and dynamic contrast enhanced MRI.

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is emerging as a valuable tool for non-invasive volumetric monitoring of the tumor vascular status and its therapeutic response. However, clinical utility of DCE-MRI is challenged by uncertainty in its ability to quantify the tumor microvasculature ([Formula: see text] scale) given its relatively poor spatial resolution (mm scale at best). To address this challenge, we directly compared DCE-MRI parameter maps with co-registered micron-scale-resolution speckle variance optical coherence tomography (svOCT) microvascular images in a window chamber tumor mouse model. Both semi and fully quantitative (Toft's model) DCE-MRI metrics were tested for correlation with microvascular svOCT biomarkers. svOCT's derived vascular volume fraction (VVF) and the mean distance to nearest vessel ([Formula: see text]) metrics were correlated with DCE-MRI vascular biomarkers such as time to peak contrast enhancement ([Formula: see text] and [Formula: see text] respectively, [Formula: see text] for both), the area under the gadolinium-time concentration curve ([Formula: see text] and [Formula: see text] respectively, [Formula: see text] for both) and [Formula: see text] ([Formula: see text] and [Formula: see text] respectively, [Formula: see text] for both). Several other correlated micro-macro vascular metric pairs were also noted. The microvascular insights afforded by svOCT may help improve the clinical utility of DCE-MRI for tissue functional status assessment and therapeutic response monitoring applications.