Introduction
Chronic rejection (CR) in solid organ and reconstructive transplantation (RT) is associated with progressive, occlusive intimal hyperplasia (IH) resulting in ischemic graft loss Four hand transplants and 1 face transplant have been lost to CR Skin biopsies can detect acute rejection (AR) but miss CR changes Early detection is key to prevent CR graft loss Sequential vascular mapping with CT angiography is fraught with radiation/contrast risks and intravascular imaging is invasive or lead to graft ischemia For the first time, we developed a non-invasive, reliable and reproducible, non-radiation, contrast-free, ultra-high resolution (UHR) 3D vascular MRI imaging strategy for preoperative (surgical planning) and perioperative (graft viability) and post-transplant (CR monitoring) applications in RT.
Results
Our non-contrast technique allowed UHR luminal and vessel wall imaging in the CF and UE tissues Volume-rendering and post-processing allowed successful 3D-reconstruction and segmenting micro/macrovasculature of CF and UE without skeletonization or dilation summarizes T1-VIBE, T2-DESS and DSI revealing exquisite detail of soft tissue anatomy (vessels, muscles, nerve, fat, ligaments, and tendons).
Figure 1. [a]: T1W image showing nreve branching after Brachial bifurcation, [b]: T2W image showing radial nerve along the forearm, [c,d]: Axial T1W AND T2W images for Diffusion imaging, [e,f]: Color coded and FA map (sagittal view of forearm), [g]: Fiber tractography for forearm nreves (and it's branches); [A,B]: 3D construction of VBIE fat-sat (nerve and vessel visualization), [C,D,E,F]: Vessel segmentation (lateral nasal, Superior labial, Inferior labial, facial, Transverse artery, Ophtalmic artery, Superficial temporal artery, External carotid); [G]: SWI Forearm image showing vasculature, [H]: Masked vasculature, [I,J]: Vessel segmentation in forearm arteries and veins. [K,L]: Digital vessels in fingers, [M,N]: 3D volume texturing Super Palmer Arch in the palmer region.
![Figure 1. [a]: T1W image showing nreve branching after Brachial bifurcation, [b]: T2W image showing radial nerve along the forearm, [c,d]: Axial T1W AND T2W images for Diffusion imaging, [e,f]: Color coded and FA map (sagittal view of forearm), [g]: Fiber tractography for forearm nreves (and it's branches); [A,B]: 3D construction of VBIE fat-sat (nerve and vessel visualization), [C,D,E,F]: Vessel segmentation (lateral nasal, Superior labial, Inferior labial, facial, Transverse artery, Ophtalmic artery, Superficial temporal artery, External carotid); [G]: SWI Forearm image showing vasculature, [H]: Masked vasculature, [I,J]: Vessel segmentation in forearm arteries and veins. [K,L]: Digital vessels in fingers, [M,N]: 3D volume texturing Super Palmer Arch in the palmer region.](/cms/asset/b52f9de3-8fbc-4789-9771-a00c8974d430/kvca_a_1233014_f0001_c.gif)
Conclusion
Current state of the art imaging in RT includes conventional imaging (3D-CT, 15/3TMRI, CT-angio, intravascular-ultrasound, plain-radiography) and stereolithography for surgical planning with limitation like radiation, renal toxic contrast or are of sub-optimal resolution to map microvessels /other structures Our approach is renal-toxic-contrast and radiation-free, increasing its safety in RT (CF or UE) or even solid organ (eg renal transplant) applications for sequential non-invasive graft monitoring of CR In addition, UHR imaging can be used for monitoring of neuroregeneration after transection/repair or transplant related nerve outcomes as well as identifying precise localization of various structures for patient screening/selection, procedural planning and sequential monitoring of macro/microvascular parameters.