Contrast-enhanced Ultrasound in Detecting Endoleaks with Failed Computed Tomography Angiography Diagnosis after Endovascular Abdominal Aortic Aneurysm Repair

Abstract

Background:Endovascular aneurysm repair (EVAR) is one of the first-line therapies of abdominal aortic aneurysms. Postoperative endoleak is the most common complication of EVAR. Computed tomography angiography (CTA), which is routine for follow-up, has side effects (e.g., radiation) and also has a certain percentage of missed diagnosis. Preliminary studies on contrast-enhanced ultrasound (CEUS) have shown that the sensitivity of CEUS for detecting endoleak is no lower than that of CTA. To investigate the advantages of CEUS, we conducted CEUS examinations of post-EVAR cases in which CTA failed to detect endoleak or could not verify the type of endoleak.Methods:Post-EVAR patients, who were clinically considered to have endoleak and met the inclusion criteria were enrolled between March 2013 and November 2014. All of the patients underwent color Doppler flow imaging (CDFI) and a CEUS examination. Size, location, microbubble dispersion, and hemodynamic characteristics of leaks were recorded. Comparison between the diagnosis of CEUS and CDFI was conducted using Fisher's exact test and clinical outcomes of all patients were followed up.Results:Sixteen patients were enrolled, and 12 (75%) had endoleaks with verified types by CEUS. Among 12 cases of endoleaks were positive by CEUS, 10 were CDFI-positive, and the four CEUS-negative cases were all negative by CDFI. The diagnostic values of CEUS and CDFI were statistically different (P = 0.008). Six patients with high-pressure endoleaks received endovascular re-intervention guided by CEUS results. One patient with type III endoleak had open surgery when endovascular repair failed.Conclusions:CEUS is a new, safe, and effective means for detection of endoleaks post-EVAR. This technique can be used as a supplement for routine CTA follow-up to provide more detailed information on endoleak and its category.

Factors predicting the instant effect of motor function after subthalamic nucleus deep brain stimulation in Parkinson’s disease

“…Bilateral STN-DBS is widely used to treat PD and its distinct effects have been confirmed [2, 3, 6, 7, 11]. Compared with the “off-medication” condition prior to surgery, bilateral STN-DBS greatly improved the motor function of PD patients in “off-medication/on-stimulation” condition 3 months after surgery in our study.…”

“…We set frequency at 130 Hz and pulse width at 60 us generally, the amplitude was progressively increased from 0 to 5–6 V with increments of 0.5–1.0 V or until side effects appeared. The optimal electrode contacts and voltage with the lowest threshold for inducing a beneficial results and the highest threshold for leading side effects were finally selected for chronic stimulation [7]. After setting up suitable parameters, we adjusted the dopaminergic medication based on the patient’s response to stimulation or just followed the preoperative medication plan.…”

“…Subsequently, bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) is used for patients with drug-refractory tremor or patients with intolerable motor complications. The benefits of STN-DBS are incontestable and have been proven by short-term and long-term follow-up studies [2–7]. …”

Contrast-enhanced US–guided Interventions: Improving Success Rate and Avoiding Complications Using US Contrast Agents

“…Enhancement can also be monitored over the region of interest continuously and for a much longer period, without a cumulative radiation burden as in CT or fluoroscopy. For this reason, CEUS has superior temporal resolution when compared with other imaging modalities, such as multisection CT, eliminating the theoretical risk of missing a delayed extravasation or enhancing abnormality (14,15).…”

Endovascular Management of Abdominal Aortic Aneurysms: the Year in Review

“…The potential benefits of contrast-enhanced ultrasound (CEUS) have been well studied [71]. CEUS may also augment CTA follow-up by providing more detail on the type and location of endoleak [72]. A meta-analysis showed CEUS to be highly sensitive for detection of type II endoleaks, especially delayed type II leaks, due to the longer scanning window period [73].…”