Multislice helical CT angiography provides the same information as a conventional angiography regarding the lumen of the popliteal artery but it provides additional clinically relevant information regarding the arterial wall such as the presence or absence of an aneurysm, the presence and extent of cystic adventitial disease and the relationship of the artery with adjacent structures such as the surrounding muscles .
Multislice helical CT angiography has several potential advantages over conventional CT or single slice helical CT. One of the major advantages is the ability to scan a large volume with thin slices during the optimal arterial contrast enhancement phase [2, 3]. The multislice CT data set can be reconstructed with thin overlapping images. Overlapping thin collimation images allow an enforced quality of the post-processing techniques. These reconstructed images are particularly useful in demonstrating the extent of the isolated stenosis. Using these post-processing techniques, multislice helical CT angiography provides more detailed and clinically relevant information as compared to conventional angiography resulting in an adjusted treatment planning according to the aetiology of the stenosis.
On the other hand, evaluation of the overall vascular status of the patient's lower limb is also important in treatment planning. Multislice helical CT angiography can still not replace conventional angiography for this purpose .
In young patients with an ischaemic leg the differential diagnosis includes an embolus, an in situ thrombosis, a thrombosed popliteal aneurysm, but also cystic adventitial disease and popliteal artery entrapment syndrome [1, 5].
In this case, multislice CT was an important tool for the diagnosis by yielding overlapping thin collimation axial images and high-quality reconstructed images. The completion arteriogram was useful in that it did not reveal any concomitant atheromatous disease.
These findings led to the diagnosis of an isolated stenosis of the popliteal artery caused by an embolus. Any other possible aetiology of the popliteal artery stenosis could be excluded by combining the findings of multislice helical CT angiography with the completion arteriogram. An accurate diagnosis was essential in this case, as treatment planning differed according to the diagnosis [1, 2, 5].