Revealing Unseen Detailed Human Vascular Anatomy of the Thumb using a Novel Contrast Agent and technique with 4D Helical Micro CT Scanner
Authors: Smythe Ciaran , Meisenheimer Douglas , Echols Scott , Benninger Brion 
Published: April 2020

INTRODUCTIONCross‐sectional imaging of human vasculature (hospital CT and MRI scans) is often enhanced by injecting contrast mediums, which classically is either iodine or gadolinium. Unfortunately, these agents exit medium sized vessels and occasionally medium to small sized vessels. Vascular pathologies can be identified from hospital CT and MRI scan widths of large to medium sized vessels especially when enhanced by 3‐D software imaging. The objective of this study was to investigate if an alternative contrast agent perfused into a donor cadaver using 1 of only 2, 4D Helical Micro CT scanners worldwide could demonstrate previously unseen detailed human vascular anatomy of the thumb.METHODSLiterature search revealed a source developed by the authors using a novel barium sulfate contrast agent which does not exit vessels and reveals medium sized (2–5 mm), small (1–2 mm), very small (less then 1mm) and micro (less then 100 microns) vessels. Human donor cadavers greater then 75 years old (N=4 donors:3M‐1F:8‐Thumbs) were chosen to assess whether the contrast agent could negotiate through elderly vessels and be imaged with the 4D helical micro CT scanner. Cadavers were initially embalmed with Freedom Art solution, then scanned with Sonosite ultrasound finger probe to assess vessel patency. Perfusing the contrast agent was conducted at the common carotid site within the neck and rescanned to assess patency of vessels in upper limb. 4D Helical Micro CT scanning was conducted post contrast perfusion and viewed with high end desktop computer software (Avizo) for 3D rendering for virtual dissection by the Sectra visualization table (VT).RESULTSThe embalming and contrast was successfully perfused into human donor cadavers. Sonosite ultrasound finger probe revealed patent medium and small vessel ultrasound images day 1, day 3, and day 7 post contrast perfusion. The perfusion technique was also deemed successful as the 4D helical micro CT scanning of the human cadaver thumbs revealed detailed thumb vascular anatomy images (micro, 8–40 microns). Each thumb was subsequently dissected wearing surgical loops which revealed patent vessels filled with contrast. DICOM files were successfully rendered into 3D images using Sectra visualization table revealing micro vasculature of the human thumb.DISCUSSIONThis study successfully conducted a unique perfusion technique to donor cadavers with a novel contrast agent illuminating previously unseen micro vasculature imaging of the human thumb region from a 4D Helical Micro CT scanner. Sonosite ultrasound finger probe was a successful tool to assess vessel patency suggesting contrast remains within the upper limb vasculature for at least 7 days.CONCLUSIONThe positive outcome from this pilot study warrants further studies which will improve our understanding of detailed vascular anatomy enabling accurate future medical simulation, artificial intelligence and developing innovative medical technology.