Abdominal Aortic Stent Grafts Combined with Peripheral Vascular Disease

Stephen D Scott, MBA, RT (R) (CT); Zorica Vranic, AS, RT (R) (CT); Michael Cullinane*, BS, RT (R) (CT)
Center for Diagnostic Imaging, St. Luke’s Hospital, Chesterfield, Missouri, USA
*Siemens Healthineers, USA
 |  2020-01-27

History

A 70-year-old male patient, suffering from an abdominal aortic aneurysm (AAA) had undergone stent grafts placement. He had a known history of peripheral vascular disease and came to the hospital for a follow-up. CT angiography (CTA) was performed for evaluation.

Diagnosis

CTA images revealed a stable infrarenal AAA, measuring 5.5 cm in diameter, with no evidence of an endoleak. Aortic and iliac stent grafts were well opacified and showed no signs of stenosis. All abdominal branches were patent. The left superficial femoral artery (SFA) was occluded at the origin without reconstitution, as was the popliteal artery (PA). The left calf vasculature was filled by collaterals. Aneurysms were visualized in the distal right SFA (2.5 cm), the right PA (1.2 cm) and the left SFA (1.8 cm).

Extensive calcified plaques along the calf vasculature were present, causing multifocal irregularities bilaterally with a diminished two-vessel runoff to the feet.

Fig. 1:
cVRT images show an overview of the scan range with (Fig. 1a) and without (Fig. 1b) bony structures.

Fig. 2:
A cVRT image (Fig. 2a) shows the stent grafts in place, without stenosis. A coronal MPR image reveals aneurysms (arrows) bilaterally in the distal SFA. A MIP image demonstrates the occluded left SFA and PA, with collaterals filling the calf vasculature.

Comments

Follow-up CT scans are routinely performed on patients with a history of stent graft placement and peripheral vascular disease. In this case, 80 kV was applied to enhance the contrast and reduce the radiation dose, combined with CARE Dose4D (real-time anatomic exposure control) and the iterative reconstruction technique SAFIRE (Sinogram Affirmed Iterative Reconstruction). Excellent image quality was achieved enabling the physicians to rule out an endoleak, confirm stent grafts patency and evaluate the peripheral vascular disease. The cinematic rendering technique improves depth and shape perceptions, allowing for an improved life-like 3D demonstration.

Examination Protocol

ScannerSOMATOM go.Up
Scan areaAbdominal aorta through lower extremities
Scan modeSpiral
Scan length1,410 mm
Scan directionCranio-caudal
Scan time42 s
Tube voltage80 kV
Effective mAs110 mAs
Dose modulationCARE Dose4D
CTDIvol2.94 mGy
DLP427 mGy cm
Rotation time0.8 s
Pitch1.2
Slice collimation32 x 0.7 mm
Slice width0.6 mm
Reconstruction increment0.6 mm
Reconstruction kernelBv36 (SAFIRE 3)
Contrast350 mg/mL
Volume100 mL
Flow rate4 mL/s
Start delayAortic bolus tracking @100 HU + 15 s

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