Detection and characterization of endoleaks following endovascular treatment of abdominal aortic aneurysms using contrast harmonic imaging (CHI) with quantitative perfusion analysis (TIC) compared to CT angiography (CTA)

PURPOSE

To show the feasibility of the detection of endoleaks following endovascular treatment of aortic aneurysms using contrast harmonic imaging (CHI) in comparison to computed tomography angiography (CTA).

MATERIALS AND METHODS

51 patients with suspected endoleaks, who underwent previous endovascular treatment for abdominal aortic aneurysm, were examined using CTA and vascular ultrasound. Biphasic CTA in all cases and digital subtraction angiography (DSA) in 8 patients were evaluated by two radiologists in consensus and served as the standard of reference. Ultrasound was performed by an experienced examiner with a multi-frequency linear transducer (2 - 4 MHz) using CHI following bolus injection of 2.4 ml of SonoVue® IV (maximum 5 ml). All images were evaluated by two observers in consensus regarding the reperfusion of the abdominal aneurysm using time intensity curve (TIC) analysis.

RESULTS

In 30 of 51 patients, endoleaks were detected concordantly in CHI and CTA. In 20 of 51 patients, no endoleak was found in CHI and CTA/DSA. In one patient, a type II endoleak could initially only be detected in CHI and was later confirmed in follow-up examinations by CTA (sens. 99%, spec. 93%, NPV 99 %, PPV 95%). TIC analysis allowed evaluation of the perfusion dynamics of endoleaks in all patients. Significant differences were found (p < 0.05, Mann Whitney U Test) regarding the perfusion within the aneurysm when an endoleak was present (10.39 ± 4.29 dB) or not present (6.42 ± 2.86 dB).

CONCLUSION

CHI with perfusion analysis allows definite detection of endoleaks, especially if contraindications for CTA are present. CHI presents an alternative for follow-up monitoring.

Contrast harmonic imaging ultrasound and perfusion imaging for surveillance after endovascular abdominal aneurysm repair regarding detection and characterization of suspected endoleaks

OBJECTIVE

Is Contrast Harmonic Imaging (CHI) comparable to computed tomography angiography (CTA) scan in detecting and characterizing suspected endoleaks after endovascular abdominal aneurysm repair in a non-selected group including reintervention procedure and branched endografts in daily practice?

MATERIAL/METHODS

In a prospective study computed tomography angiography (CTA) and contrast-enhanced ultrasound (CEUS) were performed in 30 consecutive patients (26 males, 4 females, mean age: 72 years, range: 38-87) with suspected endoleaks in follow-up (mean 13 months, range: 1-95) after endovascular abdominal aneurysm repair or procedure in dissection or penetrated ulcer of the aorta (25 infrarenal, 5 suprarenal stent grafts, mean aortic diameter 56 mm, range: 27-98). CTA was supposed to be gold standard for determining the presence of endoleaks (multislice CT, collimation 16 x 0.75 mm, 100 ml of iodized contrast agent bolus). Ultrasonography used a multi-frequency probe (1-4 MHz) with the modalities of colour coded Doppler sonography (CCDS), power Doppler (PD) combined with contrast enhancement and the technique of contrast harmonic imaging (CHI) and low mechanical index (MI < 0.2). 2.4 ml of SonoVue (Bracco, Altana Pharma GmbH, Italy) were administered to each patient intravenously as a bolus injection.

RESULTS

Out of 30 patients, 21 endoleaks were identified in CTA (6 type I or III, 15 type II), 22 in CHI. Thus, sensitivity for CHI was therefore 99%, its specificity 85% (Spearman correlation coefficient (CC) 0.92). In follow-up the localizations of endoleak type I or III exclusively detected by CHI were confirmed as true positive by angiography. Due to its dynamic characteristic CHI seemed to be more helpful in characterization of endoleaks than CTA. In case of a rupture after reintervention a type III endoleak leads to prompt intervention before receiving the result of the CT scan. Altogether, CHI failed to identify 1 combined type I and II endoleak (sensitivity 0.99). Both, CCDS and PD were positive only in 6/30 patients (CC 0.33 and 0.39). Interestingly the application of contrast agent doubles the detection rate of endoleaks (12/30) in CCDS and PD (CC 0.39).

CONCLUSION

Contrast harmonic imaging (CHI) compared to computed tomography angiography (CTA) accurately depicts endoleaks after endovascular abdominal aneurysm repair and stent-graft procedure in dissected and ulcerated aorta. It seems to be superior in characterization of the type of endoleaks and can be established in order to reduce iodized contrast agent and radiation exposure in follow-up. In contrast to CTA scan CHI can be offered to patients with chronic renal insufficiency and allows a dynamic examination and a perfusion analysis.

[Impaction of a "sausage bread" in the esophagus--first manifestation of an eosinophilic esophagitis in a 17-year-old patient]

A 17-year-old patient was transferred to the emergency room with an impacted food bolus by colleagues from the Department of Otorhinolaryngology. The examination of ear, nose and throat revealed significant amounts of saliva in both recessus piriformis, a radiologic examination of the esophagus showed a foreign body with a diameter of 1.6 cm in the region of the transitional zone of esophagus and stomach with a support level of the contrast medium. Clinical examination and laboratory tests showed no abnormalities. An emergency gastroscopy was performed. The foreign body, already evident in the barium swallow, was found in the distal esophagus. The foreign body was identified as a food bolus and gently advanced into the stomach with the aid of the gastroscope. In the stomach further food residues were detected and the examination was aborted because of increased risk of aspiration. On the next day, an elective gastroscopy was performed. Several biopsies were obtained from the esophagus because eosinophilic esophagitis (EE) was suspected due to clinical symptoms. Histological work-up showed a significant amount of eosinophilic granulocytes (> 15 eosinophils/HPF, 400 x) and reactive changes in the distal esophagus. Therefore, EE was diagnosed. Fluticasone therapy led to amelioration of symptoms and there was no evidence of recurring bolus impaction during follow-up.