Before the advent of tomographic imaging, it was postulated that decay of 90 Y to the 0+ excited state of 90Zr may result in emission of a positron–electron pair. While the branching ratio for pair-production is small (~32 × 10−6), PET has been successfully used to image 90 Y in numerous recent patients and phantom studies. 90 Y PET imaging has been performed on a variety of PET/CT systems, with and without time-of-flight (TOF) and/or resolution recovery capabilities as well as on both bismuth-germanate and lutetium yttrium orthosilicate (LYSO)-based scanners. On all systems, resolution and contrast superior to bremsstrahlung SPECT has been reported. The intrinsic radioactivity present in LYSO-based PET scanners is a potential limitation associated with accurate quantification of 90 Y. However, intrinsic radioactivity has been shown to have a negligible effect at the high activity concentrations common in 90 Y radioembolization. Accurate quantification is possible on a variety of PET scanner models, with or without TOF, although TOF improves accuracy at lower activity concentrations. Quantitative 90 Y PET images can be transformed into 3-dimensional (3D) maps of absorbed dose based on the premise that the 90 Y activity distribution does not change after infusion. This transformation has been accomplished in several ways, although the most common is with the use of 3D dose-point-kernel convolution. From a clinical standpoint, 90 Y PET provides a superior post-infusion evaluation of treatment technical success owing to its improved resolution. Absorbed dose maps generated from quantitative PET data can be used to predict treatment efficacy and manage patient follow-up. For patients who receive multiple treatments, this information can also be used to provide patient-specific treatment-planning for successive therapies, potentially improving response. The broad utilization of 90 Y PET has the potential to provide a wealth of dose–response information, which may lead to development of improved radioembolization treatment-planning models in the future.
Suprarenal endograft fixation does not lead to significant renal dysfunction, and renal artery occlusion is uncommon within 12 months. A larger study with longer follow-up is essential to determine overall effects on renal function and renal artery patency.
Background-Limited penetration into the caval wall is an important securing mechanism for inferior vena cava (IVC) filters; however, caval penetration can also cause unintentional complications. The aim of this study was to assess the incidence, severity, clinical consequences, and management of filter penetration across a range of commercially available IVC filters. Methods and Results-The MEDLINE database was searched for all studies showed evidence of organ/structure involvement. Among patients with penetration, 8% were symptomatic, 45% were asymptomatic, and 47% had unknown symptomatology. The most frequently reported symptom was pain (77%, 108 of 140). Major complications were reported in 83 patients (5%). These complications required interventions including surgical removal of the IVC filter (n=63), endovascular stent placement or embolization (n=11), endovascular retrieval of the permanent filter (n=4), and percutaneous nephrostomy or ureteral stent placement (n=3). Complications led to death in 2 patients. A total of 87% of patients (127 of 146) underwent premature filter retrieval or interventions for underlying symptoms or penetration-related complications. Conclusions-Caval penetration is a frequent but clinically underrecognized complication of IVC filter placement.Symptomatic patients accounted for nearly 1/10th of all penetrations; most of these cases had organ/structure involvement. Interventions with endovascular retrieval and surgery were required in most of these symptomatic patients.
Elective EVAR in octogenarians appears safe and effective over midterm follow-up, with a temporary decrease in renal function (14%) and postoperative lymphoceles (12%) being the most common postoperative adverse events. Advanced chronologic age is not associated with diminished procedural outcome, clinical success, or postoperative survival, compared with younger age. Because of low perioperative mortality and high procedural success, EVAR may be the preferred approach to abdominal aortic aneurysm treatment in selected elderly patients.
Surgical treatment has superior long-term patency and requires fewer reinterventions, but it is also more invasive with greater morbidity and mortality compared to endovascular treatment. Endovascular techniques may be preferable in patients with significant co-morbidities, concomitant aortic disease, or indeterminate symptoms.
Dilatation of the CIA is significant after EVAR, and it is more pronounced in ectatic iliac arteries. Although ectatic iliac arteries appear to be suitable sealing zones in the short term, continued follow-up is mandatory.
Venous thrombosis of pancreas transplant allografts often leads to graft loss. We evaluated the efficacy of emergent endovascular techniques to salvage thrombosed pancreatic allografts in a series of six patients. Of the 76 pancreas transplants performed between 2002 and 2006, six patients were diagnosed with venous thrombosis on MRI between 2 and 28 days posttransplant (mean, 9 days). Five patients were systemic-enteric (donor portal vein anastomosis to recipient iliac vein) and one patient was portal-enteric (donor portal vein anastomosis to recipient superior mesenteric vein). Conventional venography confirmed the diagnosis of venous thrombosis in all patients. One patient was treated with catheter-directed venous thrombolysis and balloon thrombectomy. Another patient was treated with rheolytic thrombectomy alone. The remaining four patients were treated with a combination of these mechanical and thrombolytic techniques. Completion venography revealed >50% clot reduction and resumption of venous drainage in all patients. One patient required additional intervention 16 days later for recurrent thrombosis. Two patients required metal stent placement for anastomotic stenoses or kinks. One patient required pancreatectomy 36 h after attempted salvage secondary to a major hemorrhage and graft necrosis. Two patients recovered pancreatic function initially but lost graft function at 8 and 14 months, respectively, from severe chronic rejection. Patient survival was 100%, long-term graft survival was 50%, rethrombosis rate was 16.6%, and graft loss from rejection was 33%. In conclusion, early recognition and treatment of venous thrombosis after pancreas transplantation has acceptable morbidity and no mortality using short-term endovascular pharmacomechanical therapy.
Resin-based Y radioembolization can provide palliative control of unresectable and failed first-line chemotherapy ICC in a salvage setting with acceptable side effects.
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