PMC5465410_01
Contrast CT obtained in December 2013 showing an IVCF (arrow) that appeared to have been displaced outside the blood vessel. CT: computed tomography, IVCF: inferior vena cava filter. Arrow, IVCF; 1, inferior vena cava
1349-7235-56-0931-g001.jpg
PMC5465410_01_1349-7235-56-0931-g001.jpg
g001
Council dyspnea scale grade 1). Contrast computed tomography (CT) did not reveal a recurrence of PTE; however, the IVCF appeared to have been displaced outside the blood vessel (Fig. 1).
(A) A CT angiogram on admission showing a dilated and obstructed IVC (1) at the site of the indwelling IVCF (arrow). Blood flow below the site of IVC occlusion returned from the azygos vein to the superior vena cava via the collateral circulation (2, 3). In addition, both sides of the iliac vein (4) were markedly expanded. (B) A 3-dimensional image constructed from the contrast CT images showing the occlusion of the IVC and a detailed view of the collateral circulation. CT: computed tomography, IVC: inferior vena cava, IVCF: inferior vena cava filter. Arrow, IVCF; 1, IVC; 1', the remaining IVC from the renal vein of the head side; 2, the ascending lumbar vein; 3, the lumbar vein; 4, the iliac vein
1349-7235-56-0931-g002.jpg
PMC5465410_01_1349-7235-56-0931-g002.jpg
g002
Tochigi, Japan) with a slice thickness of 2 mm, 0.35 s/rotation, and three-dimensional (3D) image reconstruction revealed the complete obstruction of the IVC at the site of the IVCF placement. The IVC showed aneurysm-like changes; blood flow below the occluded site of the IVC returned from the azygos vein to the superior vena cava via the collateral circulation (Fig. 2). There was no recurrence of CTEPH or obvious lung lesions.
A retrospective review of follow-up contrast CT in 2006 showing thrombi (triangle) in the IVCF. CT: computed tomography, IVCF: inferior vena cava filter. Arrow, IVCF; 1, inferior vena cava
1349-7235-56-0931-g003.jpg
PMC5465410_01_1349-7235-56-0931-g003.jpg
g003
A retrospective review of follow-up contrast CT in 2006 revealed thrombi in the IVCF, but no DVT or collateral circulation were detected (Fig. 3).
An angiogram of the IVC and left iliac vein confirming IVC occlusion at the site of the IVCF and the presence of marked collateral circulation, similar to the contrast CT findings. IVC: inferior vena cava, IVCF: inferior vena cava filter, CT: computed tomography (Arrow, IVCF; 1, IVC; 2, ascending lumbar vein; 3, iliolumbar vein; 4, iliac vein; 5, azygos vein; 6, hemi azygos vein)
1349-7235-56-0931-g004.jpg
PMC5465410_01_1349-7235-56-0931-g004.jpg
g004
IVC and the left iliac vein confirmed IVC occlusion at the site of the IVCF and the presence of significant collateral circulation, similar to that which was found by contrast CT (Fig. 4, 5). In addition, DVT was observed in the lower limb, and collateral circulation could not be detected.
A schematic illustration of the 3-dimensional image constructed from the contrast CT images and angiography of the IVC. CT: computed tomography, IVC: inferior vena cava, IVCF: inferior vena cava filter
1349-7235-56-0931-g005.jpg
PMC5465410_01_1349-7235-56-0931-g005.jpg
g005
IVC and the left iliac vein confirmed IVC occlusion at the site of the IVCF and the presence of significant collateral circulation, similar to that which was found by contrast CT (Fig. 4, 5). In addition, DVT was observed in the lower limb, and collateral circulation could not be detected.