Abstract
Background Most free flap reconstruction complications involve vascular compromise. Evaluation
of vascular anatomy provides considerable information that can potentially minimize
these complications. Previous reports have shown that contrast-enhanced computed tomography
is effective for understanding three-dimensional arterial anatomy. However, most vascular
complications result from venous thromboses, making imaging of venous anatomy highly
desirable.
Methods The phase-lag computed tomography angiography (pl-CTA) technique involves 64-channel
(virtually, 128-channel) multidetector CT and is used to acquire arterial images using
conventional CTA. Venous images are three-dimensionally reconstructed using a subtraction
technique involving combined venous phase and arterial phase images, using a computer
workstation.
Results This technique was used to examine 48 patients (12 lower leg reconstructions, 34
head and neck reconstructions, and 2 upper extremity reconstructions) without complications.
The pl-CTA technique can be used for three-dimensional visualization of peripheral
veins measuring approximately 1 mm in diameter.
Conclusion The pl-CTA information was especially helpful for secondary free flap reconstructions
in the head and neck region after malignant tumor recurrence. In such cases, radical
dissection of the neck was performed as part of the first operation, and many vessels,
including veins, were resected and used in the first free-tissue transfer. The pl-CTA
images also allowed visualization of varicose changes in the lower leg region and
helped us avoid selecting those vessels for anastomosis. Thus, the pl-CTA-derived
venous anatomy information was useful for exact evaluations during the planning of
free-tissue transfers.
Keywords
phase-lag computed tomography angiography - computed tomography angiography - venous
anatomy - venous imaging
