Evaluation of contrast-enhanced MR angiography in the follow-up of visceral arterial aneurysms after coil embolization

Ultra-short Echo-time MR Angiography Combined with a Modified Signal Targeting Alternating Radio Frequency with Asymmetric Inversion Slabs Technique to Assess Visceral Artery Aneurysm after Coil Embolization

Contrast-enhanced CT and MR angiography are widely used for follow-up of visceral artery aneurysms after coil embolization. However, potential adverse reactions to contrast agents and image deterioration due to susceptibility artifacts from the coils are major drawbacks of these modalities. Herein, we introduced a novel non-contrast-enhanced MR angiography technique using ultra-short TE combined with a modified signal targeting alternating radio frequency with asymmetric inversion slabs, which could provide a serial hemodynamic vascular image with fewer susceptibility artifacts for follow-up after coil embolization.

Can Color Doppler Ultrasound Be Effectively Used as the Follow-Up Modality in Patients Undergoing Splenic Artery Aneurysm Embolization? A Correlational Study between Doppler Ultrasound, Magnetic Resonance Angiography and Digital Subtraction Angiography

Splenic artery aneurysm (SAAs) rupture is associated with a high mortality rate. Regular surveillance with imaging before and after intervention is crucial to guide best evidence treatment. The following study aimed to determine the efficacy of color Doppler ultrasound imaging (DUS) compared to digital subtraction angiography (DSA) and magnetic resonance angiography (MRA) as a follow-up modality after selective coil embolization of true SAAs. We analyzed data from 20 patients, 15 females (48.1 ± 16.1 years) undergoing selective SAA coil embolization using detachable fibered embolization coils. Imaging using DUS, MRA, and DSA was performed 3 months after the initial embolization or the consequent re-embolization procedure. Primary clinical success, defined as Class I aneurysm occlusion, on 3-month follow-up was seen in 16 (80.0%) patients. DUS had a sensitivity of 94.4% and a specificity of 42.9% when compared to DSA and 92.3% and 30%, respectively, when compared to MRA in identifying Class I aneurysm occlusion. The positive predictive value (PPV) of DUS in identifying the need for re-embolization was 75.0%, while the NPV of DUS in these terms was 90.5%. DUS showed a high sensitivity in detecting aneurysm occlusion and clinical success, simultaneously exhibiting poor specificity. Still, with caution, this follow-up modality could be used for monitoring select low-risk patients after selective embolization of SAAs. DUS could provide a higher cost-to-benefit ratio, enabling more systematic post-procedural follow-up, as it is far more commonly used compared to MRA and non-invasive compared to DSA.

Contrast-enhanced magnetic resonance angiography for monitoring an embolized renal artery aneurysm: A case report and literature review

This case report describes a 69-year-old male patient with a renal artery aneurysm that was followed up with contrast-enhanced magnetic resonance angiography at 8 months after coil embolization treatment. Due to the disappearance of residual lumen with few metal artifacts, the therapeutic effect was satisfactory. At present, the indications for the treatment of renal artery aneurysms are still controversial and there are very few reports of postembolization images of renal artery aneurysms, with no criteria for reintervention and few reports for monitoring the embolized aneurysms. Further reports and research are still needed for the treatment of this rare disease.

A systematic review on clinical features and management of true giant splenic artery aneurysms

BACKGROUND

True giant splenic artery aneurysms (GSAAs) >5 cm are rare and present unique therapeutic challenges. The aim of this study was to evaluate the anatomic and clinical characteristics of these lesions and the current surgical and endovascular techniques available for their treatment.

METHODS

A systematic review of the literature from 2004 to 2018 and the personal experience of the authors with management of GSAAs are presented. A total of 92 GSAA cases were reviewed. Analyses were performed on anatomic and clinical features and management modalities and outcomes of GSAA, including reintervention, morbidity, and mortality.

RESULTS

GSAA presented at a mean age of 56.1 ± 17.3 years, with no sex predilection; 73% were symptomatic at presentation. Abdominal pain was the presenting symptom in >50% of cases; 34% percent were ruptured, with an overall mortality rate of 12.5%. This group often presented with gastrointestinal bleeding or hemodynamic collapse. The aneurysms were almost evenly distributed across the splenic artery and were not uncommonly associated with arteriovenous fistula formation (8.7%). There were 88 patients who had surgical (53.4%), endovascular (44.3%), or combination (2.3%) therapy. The most commonly performed procedure was aneurysmectomy and splenectomy with or without additional resection. Overall, surgical treatment had a lower morbidity (P = .041) than endovascular therapy and comparable reintervention and mortality rates.

CONCLUSIONS

GSAAs are uncommon vascular lesions, with distinct clinical features and aneurysm characteristics. Considering their high risk of rupture, timely diagnosis and management are essential to attain a satisfactory outcome. Surgery remains the standard treatment of these lesions. Endovascular intervention is a viable alternative in high-risk patients, particularly those with lesions <10 cm or with anomalous origin.

Selective occlusion of splenic artery aneurysms with the coil packing technique: the impact of packing density on aneurysm reperfusion correlated between contrast-enhanced MR angiography and digital subtraction angiography

PURPOSE

The aim was to evaluate the relationship between coil packing densities after splenic artery aneurysm (SAA) treatment using detachable microcoils and rates of SAA reperfusion and to suggest a post-treatment surveillance protocol using contrast-enhanced MRA.

MATERIALS AND METHODS

Evaluated were 16 patients (4 men; mean age 46.7), who underwent true SAA embolization using detachable microcoils (Concerto, Medtronic). SAAs were treated by selective coil packing (CP) or stent-assisted coil exclusion (SAC). Contrast-enhanced magnetic resonance angiography (CE-MRA) and digital subtraction angiography (DSA) were performed at 3 months post-procedure and correlated.

RESULTS

Primary CP was used in 13 patients, while SAC was used in three patients. On follow-up, complete aneurysm occlusion was seen in seven patients (43.8%). Sac reperfusion occurred in nine patients (56.2%) and was demonstrated in all CE-MRA and six DSA studies. Mean aneurysm packing density was 20.10 ± 8.05% for the CP group and 32.90 ± 11.95% for the SAC group (p = 0.038). There was a significant difference in the incidence of aneurysm sac reperfusion on CE-MRA study between CP and SAC (9 vs. 0). No sac reperfusion was seen in aneurysms with packing densities ≥ 29%, irrespective of either embolization method.

CONCLUSION

Favorable midterm results for coil packing of SAAs seem to depend on the coil packing density with a coil volume approximately a quarter of the aneurysm volume being most effective. Follow-up should involve the use of CE-MRA as this modality has been shown to be superior over DSA in detecting aneurysm reperfusion and coil compaction.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Aneurysm resection and vascular reconstruction for true aneurysm at the initial segment of splenic artery

The aneurysms at the initial segment of splenic artery are rare. This paper aimed to investigate the methods to treat the true aneurysm at the initial segment of splenic artery by aneurysmectomy plus vascular reconstruction. Retrospectively reviewed were 11 cases of true aneurysm at the initial segment of splenic artery who were treated in our hospital from January 2000 to June 2013. All cases were diagnosed by color ultrasonography, computer tomography (CT) and angiography. Upon resection of the aneurysm, the auto-vein transplantation was performed in situ between the hepatic artery and the distal part of the splenic artery in 1 case; the artificial vessel bypass was done between the infra-renal aorta and distal portion of the splenic artery in 7 cases; the splenectomy was done in 2 cases; the splenectomy in combination with ligation of multiple small aneurysms were performed in 1 case. All cases were cured and discharged from the hospital 10-14 days after operation. A 1-14 year follow-up showed that 9 cases survived, and 2 cases died, including 1 case who died of acute myocardial infarction 2 years after aorta-splenic artery bypass operation and 1 case who died of acute cerebral hemorrhage 5 years after aneurysm resection and the splenectomy. Among 6 cases receiving aorta-splenic artery bypass, 1 gradually developed stenosis at anatomosed site, which eventually progressed to complete occlusion 2 years to 6 years after operation, without suffering from splenic infarction because the spleen was supplied by the short gastric vessel and its collaterals. The other 5 cases receiving aorta-splenic artery bypass and 1 case undergoing autologous vascular transplantation did not develop stricture or pseudoaneurysm at the stoma. Our study showed that the aneurysmectomy plus vascular reconstruction is a better treatment for aneurysm at the initial segment of splenic artery.

Computed tomography angiography and magnetic resonance angiography imaging of the mesenteric vasculature

Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are highly accurate cross-sectional vascular imaging modalities that have almost completely replaced diagnostic catheter angiography for the evaluation of the mesenteric vasculature. CTA is the technique of choice when evaluating patients with suspected mesenteric ischemia; it permits to differentiate between occlusive and nonocclusive etiologies, to evaluate indirect signs of bowel ischemia, and in some instances, to provide alternative diagnoses. MRA has the advantage of not using ionizing radiation and iodinated contrast agents and can be appropriate in the nonacute setting. Both CTA and MRA are suitable for the assessment of patients with suspected chronic mesenteric ischemia, allowing to evaluate the degree of atherosclerotic steno-occlusive disease and the existence of collateral circulation, as well as other nonatherosclerotic vascular pathologies such as fibromuscular dysplasia and median arcuate ligament syndrome. CTA provides excellent depiction of visceral aneurysms and has an important role to plan therapy for both occlusive and aneurysmal diseases and in the follow-up of patients after open or endovascular mesenteric revascularization procedures. This article provides an introduction to the CTA and MRA imaging protocol to study the mesenteric vasculature, the imaging findings in patients presenting with acute and chronic mesenteric ischemia and visceral aneurysms, and the value of these imaging techniques for therapy planning and follow-up.