Determination of lower limb microvasculature by intrafemoral arterial injection using computed tomography-assisted...

Computed tomography-assisted angiography (CTA) for lower limb vasculature can identify perforators only as small as 1 mm in diameter. The technique does not clearly show the microvascularity in subdermal layers of the skin. This study investigated a novel method of CTA using intrafemoral injection of contrast medium instead of intravenous injection to display the vascular anatomy of small perforators with a diameter less than 1 mm in the lower extremities of rabbits.

Posterior thigh perforator surgery was performed for 15 New Zealand rabbits weighing 2.5 to 3.5 kg. Five rabbits underwent anatomic dissection to determine the vascular anatomy of the posterior thigh perforator and its location relative to adjacent structures. Of the remaining 10 rabbits, 5 were subjected to CTA scanning after injection of iodine contrast through a microcatheter inserted into the femoral artery, and 5 were subjected to CTA scanning through venous injection of contrast media. The latter group was designated as the control group (10 extremities). Images were viewed using a dedicated workstation. Postoperative outcomes and complications were monitored for 7 days after the procedure.

All the CTA images of intraartery administration clearly showed that the posterior thigh perforators originated from the popliteal artery. Injection of contrast agent through the femoral artery improved resolution of the CTA, enabling visualization of perforator arteries with diameters in the range of 0.3 to 0.4 mm. The images of the control group indicated the course of the perforator in the muscle of only six legs. The images of the remaining four legs did not display the perforator. The CTA-treated animals recovered without any complications. The anatomic dissection matched the CTA mapping.

Computed tomography-assisted angiography using intraarterial injection of contrast media enables visualization of vessels smaller than 1 mm in diameter. The described animal model also showed the presence of vascular branches in the subdermis. This imaging technique may help in the preoperative design of perforator flaps for use in clinical practice.

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