[The problem with endoleakage in endoluminal therapy]

[Type III endoleaks at follow-up of covered descending thoracic aortic stent-grafts: report of 3 patients]

PURPOSE

To describe the imaging work-up and management of type III endoleaks detected after covered stent-graft treatment of descending thoracic aortic aneurysms.

PATIENTS AND METHODS

Retrospective study of circumstances surrounding the diagnosis, management and outcome type III endoleaks occuring in 3 of 18 patients following covered stent-graft treatment of descending thoracic aortic aneurysms between April 1998 and July 2005. The endoleaks were detected at a mean follow-up of 22 months (19-24 months) after stent-graft placement.

RESULTS

The type III endoleaks were detected on scheduled follow-up CT examinations in asymptomatic patients. Endovascular management was proposed at a mean interval time of 4.4 months (1 week - 11 months) after diagnosis of the endoleak, and was successful in all 3 cases. One patient died 1 month after endovascular repeai of the leak, 1 patient required surgical management at 14 months for new recurrence, and 1 patient had a favorable outcome at 2 months.

CONCLUSION

Follow-up of patients after covered stent-graft treatment of descending thoracic aortic aneurysms is required. Prompt endovascular repair of delayed complications may be possible, but surgical management may become necessary.

Assessment of Automatic Vessel Tracking Techniques in Preoperative Planning of Transluminal Aortic Stent Graft Implantation

OBJECTIVE

To evaluate automatic vessel tracking techniques in the course of preoperative planning prior to transluminal aortic endograft implantation by comparing accuracy, reproducibility, and postprocessing time with source image and volume-rendered analysis methods.

METHODS

Multislice computed tomography datasets of 5 patients with abdominal aortic aneurysms were preoperatively examined, performing volumetric analysis of diameter and position of renal artery orifices, aneurysmal neck, maximal aneurysmal extension, aortic bifurcation, and iliac arteries and bifurcation. Analysis was realized by utilizing transverse datasets, volume rendering, and automated vessel tracking strategies (MxView, Philips, Best, The Netherlands). Measurement techniques were evaluated by 2 independent readers 3 times for each patient and measurement modality. Statistical analysis evaluated accuracy of the measurements and intra- and interobserver reliability. Postprocessing time was documented.

RESULTS

Using transverse source datasets, intraobserver reliability ranged from 0.49 to 0.58. Intraobserver reliability improved to 0.7 to 0.98 when volume-rendered datasets were evaluated. Interobserver variability for transverse and volume-rendered datasets ranged from 0.49 to 0.76 and 0.70 to 0.96, respectively. Automated vessel tracking datasets did not demonstrate any intra- or interobserver variability. Based on transverse datasets, the length and diameter of iliac arteries and location and diameter of the aneurysmal neck were measured as statistically different in all cases in contrast to volume rendering and automated segmentation techniques. Postprocessing time consumption for measurements based on transverse, volume-rendered, and automated tracking segmentation datasets averaged 3.32 minutes, 25.43 minutes, and 2.24 minutes, respectively.

CONCLUSIONS

Preoperative measurements improve significantly if datasets are evaluated based on volume-rendering techniques. This time-consuming procedure can be shortened, while further reducing observer variability, with automatic segmentation techniques.