Computerized modeling based on spiral CT data for noninvasive determination of aortic stent-graft length

Measuring of Abdominal Aortic Aneurysm with Three-Dimensional Computed Tomography Reconstruction before Endovascular Aortic Aneurysm Repair

PURPOSE

Conventional computed tomography (CT) is the gold standard method for case planning for endovascular aortic aneurysm repair (EVAR). However, aortography with a marking catheter is needed for measuring the actual length of an aneurysm. With advances in imaging technology, a 3-dimensional (3D) workstation can obviate the need for the aortography. The objective of this study was to determine whether a 3D workstation could obviate the need for aortography for EVAR.

MATERIALS AND METHODS

One vascular surgeon and 1 interventional radiologist retrospectively assessed axial CT scans and reformatted the 3D CT scans by using the iNtuition workstation (TeraRecon Inc., San Mateo, CA, USA) for 25 patients who underwent EVAR. Four measurements of diameter and length were obtained from each modality. The actual length of an aneurysm for the proper graft was decided by 2 observers by reviewing the aortography with a marking catheter.

RESULTS

The measurements from the 2 modalities were reproducible with intraobserver correlation coefficients of 0.89 to 1.0 for conventional CT and 0.98 to 1.0 for 3D workstation. Interobserver correlation coefficients were 0.29 to 0.95 for conventional CT and 0.85 to 0.99 for the 3D workstation. The length of the aneurysm for proper main graft coincided in 18 and 14 patients according to the conventional CT scan and in 21 and 18 patients according to the 3D workstation, respectively.

CONCLUSION

The interobserver agreement in planning EVAR was significantly better with the iNtuition 3D workstation. But aortography with a marking catheter may still be needed for selecting the proper graft.

Vascular Imaging: An Unparalleled Decade

Vascular imaging techniques, such as catheter angiography, ultrasound, computed tomography (CT), and magnetic resonance (MR), have all undergone unprecedented innovation and incredible technological leaps in the last 10 years. Ultrasound, CT, and MR have progressed in acquisition speed, resolution, and accuracy to the point that they have now supplanted the former mainstay, invasive catheter-based angiography, despite the advent of digitized angiographic image recording. This review explores the advantages and shortcomings of each technique and how they have changed the diagnosis and assessment of the cardiovascular system for endovascular intervention.

Vascular imaging: an unparalleled decade

Vascular imaging techniques, such as catheter angiography, ultrasound, computed tomography (CT), and magnetic resonance (MR), have all undergone unprecedented innovation and incredible technological leaps in the last 10 years. Ultrasound, CT, and MR have progressed in acquisition speed, resolution, and accuracy to the point that they have now supplanted the former mainstay, invasive catheter-based angiography, despite the advent of digitized angiographic image recording. This review explores the advantages and shortcomings of each technique and how they have changed the diagnosis and assessment of the cardiovascular system for endovascular intervention.

Abdominal aortic aneurysms: virtual imaging and analysis through a remote web server

The study describes the application of a web-based software in the planning of the endovascular treatment of abdominal aortic aneurysms (AAA). The software has been developed in the framework of a 2-year research project called Aneurysm QUAntification Through an Internet Collaborative System (AQUATICS); it allows to manage remotely Virtual Reality Modeling Language (VRML) models of the abdominal aorta, derived from multirow computed tomography angiography (CTA) data sets, and to obtain measurements of diameters, angles and centerline lengths. To test the reliability of measurements, two radiologists performed a detailed analysis of multiple 3D models generated from a synthetic phantom, mimicking an AAA. The system was tested on 30 patients with AAA; CTA data sets were mailed and the time required for segmentation and measurement were collected for each case. The Bland-Altman plot analysis showed that the mean intra- and inter-observer differences in measures on phantoms were clinically acceptable. The mean time required for segmentation was 1 h (range 45-120 min). The mean time required for measurements on the web was 7 min (range 4-11 min). The AQUATICS web server may provide a rapid, standardized and accurate tool for the evaluation of AAA prior to the endovascular treatment.