Images of the month 2: Pulmonary artery pseudoaneurysm formation within uterine leiomyosarcoma metastases

We present a rare case of pulmonary artery pseudoaneurysm formation in leiomyosarcoma metastases with evidence of acute bleeding and subsequent interventional radiological management.

Progressive Device Failure at Long Term Follow Up of the Nellix EndoVascular Aneurysm Sealing (EVAS) System

OBJECTIVE

High rates of midterm failure of the Nellix EndoVascular Aneurysm Sealing (EVAS) System resulted in device withdrawal from the UK market. The study aim was to report long term Nellix EVAS outcomes and management of a failing device.

METHODS

A retrospective review of EVAS procedures at a tertiary unit was performed. Device failure was defined as a triad of stent migration, stent separation, and secondary sac expansion, or any intervention for type 1 endoleak, device rupture, or explant.

RESULTS

161 (male n = 140, female n = 21) patients with a median follow up of 6.0 (IQR 5.0-6.6) years were included. Freedom from all cause mortality estimate at six years was 41.5%. There were 70 (43.5%) device failures with a freedom from device failure estimate at six years of 32.3%. Failure was the result of sac expansion (n = 41), caudal stent migration (n = 36), stent separation (n = 26), and secondary AAA rupture (n = 15). A substantial number of type 1 endoleaks was present (1a n = 33, 1b n = 11), but the type 2 endoleak rate was low at 3.7%. Some 36 (22.4%) patients required re-intervention. Twenty-one patients underwent explant with no 30 day deaths. Six patients underwent Nellix-in-Nellix application (NINA) with one early death from bowel ischaemia and one patient who died later from non-aneurysm related cause. Two NINA patients have ongoing sac expansion and two have had thrombosis of a Nellix limb or visceral stent. Proximal embolisation was only successful in one of six cases.

CONCLUSION

The long term failure rate of Nellix EVAS is high. All patients with a device must be informed and be enrolled in enhanced surveillance. EVAS explant is an acceptable technique with favourable outcomes. Management by open explant, if the patient is fit, should be considered early and offered to those with device failure.

Gadofosveset-enhanced thoracic MR venography: a comparative study evaluating steady state imaging versus conventional first-pass time-resolved dynamic imaging

Background Dedicated blood-pool contrast agents combined with optimal angiographic protocols could improve the diagnostic accuracy of thoracic magnetic resonance angiography (MRA). Purpose To assess the clinical utility of Gadofesveset-enhanced imaging and compare an optimized steady-state (SS) sequence against conventional first-pass dynamic multi-phase (DMP) imaging. Material and Methods Twenty-nine patients (17 men, 12 women; mean age = 42.7, age range = 18-72 years) referred for MR thoracic venography were recruited. Imaging was performed on a 1.5T MRI system. A blood-pool contrast agent (Gadofesveset) was administered intravenously. Thirty temporal phases were acquired using DMP. This was immediately followed by a high-resolution SS sequence. Three radiologists in consensus reviewed seven thoracic vascular segments after randomizing the acquisition order. Image quality, stenoses, thromboses, and artifacts were graded using a categorical scoring system. The image quality for both approaches was compared using Wilcoxon's signed-rank test. McNemar's test was used to compare the proportions of stenosis grades, thrombus and artifacts. Results SS had significantly better image quality than DMP (3.14 ± 0.73 and 2.92 ± 0.60, respectively; P < 0.001). SS identified fewer stenoses (>50%) than DMP; the differences in stenosis categorizations was statistically significant ( P = 0.013). There was no significant difference in the proportions of vessels with thromboses ( P = 0.617). DMP produced more artifacts than SS (101 versus 85); however, the difference was not statistically significant ( P = 0.073). Conclusion Gadofesveset-enhanced thoracic angiography is clinically feasible. SS imaging produces better image quality and fewer artifacts than conventional DMP imaging.

Appearance of the Nellix endoprosthesis on postoperative imaging: implications for patient and device surveillance

The Nellix stent graft has novel features that influence interpretation of imaging follow-up, in particular, the use of endobags that seal the aneurysm sac. The polymer within the endobags contains a small amount of contrast medium, which causes a predictable temporal change in appearances. Understanding of these features allows correct image evaluation. In this article, we review the appearance of Nellix on computed tomography, ultrasound, magnetic resonance imaging, and plain radiography. We describe the special considerations that are important to consider when reviewing imaging, including endobag position and seal, endobag configuration, endobag and polymer maturation, and endobag gas. Detection of complications is discussed, with suggestion of a follow-up protocol based on the authors' experience.

Radiological Evaluation of Abdominal Endovascular Aortic Aneurysm Repair

Endovascular aortic aneurysm repair (EVAR) is an alternative to open surgical repair of aortic aneurysms offering lower perioperative mortality and morbidity. As experience increases, clinicians are undertaking complex repairs with hostile aortic anatomy using branched or fenestrated devices or extra components such as chimneys to ensure perfusion to visceral branch vessels whilst excluding the aneurysm. Defining the success of EVAR depends on both clinical and radiographic criteria, but ultimately depends on complete exclusion of the aneurysm from the circulation. Aortic stent grafts are monitored using a combination of imaging modalities including computed tomography angiography (CTA), ultrasonography, magnetic resonance imaging, plain films, and nuclear medicine studies. This article describes when and how to evaluate aortic stent grafts using each of these modalities along with the characteristic features of several of the main stent grafts currently used in clinical practice. The commonly encountered complications from EVAR are also discussed and how they can be detected using each imaging modality. As the radiation burden from serial follow up CTA imaging is now becoming a concern, different follow-up imaging strategies are proposed depending on the complexity of the repair and based on the relative merits and disadvantages of each imaging modality.

Infectious aortitis in a liver transplant recipient

The development of an abdominal aortic aneurysm secondary to infectious aortitis following solid organ transplantation is a rare event that in the absence of surgical intervention, can lead to uncontrolled sepsis, catastrophic hemorrhage and death. Arterial allografts have been a viable surgical option for the past 30 years, although operative modalities have undergone a paradigm shift in recent years. We describe the first case in the literature of a liver transplant recipient who developed an infrarenal aortic aneurysm secondary to Salmonella bacteraemia, which was treated successfully with aortic allograft transplantation.

Endovascular occlusion of a ruptured popliteal artery aneurysm

Popliteal artery aneurysms are the most common of the peripheral aneurysms. Rupture is a rare complication of these aneurysms. Here we present a case of a ruptured popliteal aneurysm in a patient with severe joint disease and immobility due to rheumatoid arthritis. The condition was treated endovascularly with an Amplatzer arterial occlusion device. The aneurysm was successfully thrombosed without inducing critical limb ischemia, as the distal popliteal was chronically occluded. Ligation of peripheral aneurysms is an infrequent treatment without simultaneous bypass graft placement. Endovascular occlusion of ruptured popliteal aneurysms should be considered a valid therapeutic strategy where exclusion bypass is not required due to distal arterial occlusion.

Imaging patients with myeloma

Multiple myeloma (MM) is a neoplastic proliferation of plasma cells within the bone marrow. The disease is characterized by a plasma cell infiltrate of the bone marrow, osteolytic bone lesions, and the presence of monoclonal protein in the serum or urine with extraosseous involvement by disease less common. Although the skeletal survey has long been the standard investigation in these patients, there have been significant recent advances in computed tomography (CT), magnetic resonance imaging (MRI), and functional imaging. We present a comprehensive review of the evidence for the use of each of these studies in the diagnosis, prognosis, assessment of complications, and response evaluation in patients with MM.