What MRI Can Tell You About Your Kidneys: Morphometric Analysis of Novel Vascular Images

Chronic Kidney Disease (CKD) is a common disease among adults in the United States. One of the leading causes of death of patients with end-stage CKD is vascular disease. We have developed a novel MRI technique Quantitative Ultrashort Time-to-Echo Contrast Enhanced (QUTE-CE) MRA, which produces high-contrast vascular images and uses a contrast agent safe for CKD subjects. Morphometric analysis of the vessels was performed using two approaches Ð a manual approach done in 3D Slicer and a semi-automatic approach using Vascular Modeling ToolKit (VMTK). Using a manual approach, anteroposterior (AP) and transverse (T) diameters were measured in the inferior vena cava (IVC) and aorta. IVC has an elliptical cross-section and transverse diameters were about twice AP diameter (22.1 ± 2.6 mm vs 12.3 ± 1.1 mm). While for the aorta, cross-section was circular with transverse and AP diameters within standard deviation (17.6 ± 4.6 mm vs 16.5 ± 4.0 mm). Due to this morphological difference, veins must be assessed along two axes but only one axis is necessary for artery diameter extraction. Using the VMTK semi-automatic approach, vessel diameters were extracted from the arteries and veins. The aorta diameter measurements were within standard deviation between the manual approach (17.1 ± 4.3 mm) and the semi-automatic approach (16.3 ± 3.8 mm). The morphology difference between them could potentially aid the automatic artery/vein segmentation, enabling assessment of both the renal arteries and veins. These results lay the groundwork for further studies which could lead to insights on vascular abnormalities and kidney disease.