Diagnostic sensitivity of multidetector-row spiral computed tomography angiography in the evaluation of type-II endoleaks and their source: comparison between axial scans and reformatting techniques

Design, construction and mechanical testing of digital 3D anatomical data-based PCL-HA bone tissue engineering scaffold

The study aims to investigate the techniques of design and construction of CT 3D reconstructional data-based polycaprolactone (PCL)-hydroxyapatite (HA) scaffold. Femoral and lumbar spinal specimens of eight male New Zealand white rabbits were performed CT and laser scanning data-based 3D printing scaffold processing using PCL-HA powder. Each group was performed eight scaffolds. The CAD-based 3D printed porous cylindrical stents were 16 piece × 3 groups, including the orthogonal scaffold, the Pozi-hole scaffold and the triangular hole scaffold. The gross forms, fiber scaffold diameters and porosities of the scaffolds were measured, and the mechanical testing was performed towards eight pieces of the three kinds of cylindrical scaffolds, respectively. The loading force, deformation, maximum-affordable pressure and deformation value were recorded. The pore-connection rate of each scaffold was 100 % within each group, there was no significant difference in the gross parameters and micro-structural parameters of each scaffold when compared with the design values (P > 0.05). There was no significant difference in the loading force, deformation and deformation value under the maximum-affordable pressure of the three different cylinder scaffolds when the load was above 320 N. The combination of CT and CAD reverse technology could accomplish the design and manufacturing of complex bone tissue engineering scaffolds, with no significant difference in the impacts of the microstructures towards the physical properties of different porous scaffolds under large load.

Two-dimensional versus three-dimensional CT angiography in analysis of anatomical suitability for stentgraft repair of abdominal aortic aneurysms

BACKGROUND

The morphological analysis prior to endovascular abdominal aneurysm repair (EVAR) plays an important role in long-term outcomes. Post-imaging analysis of computed tomographic angiography (CTA) by three-dimensional reconstruction with central lumen line detection (CLL 3D-CTA) enables measurements to be made in orthogonal slices. This might be more precise than equal post-imaging analysis in axial slices by two-dimensional computed tomographic angiography (2D-CTA).

PURPOSE

To evaluate the intra- and interobserver variability of CLL 3D-CTA and 2D-CTA post-imaging analysis methods and the agreement between them in pre-EVAR suitability analysis of patients with abdominal aortic aneurysm (AAA).

MATERIAL AND METHODS

Anonymized CTA data-sets from 70 patients with AAA were analyzed retrospectively. Length measurements included proximal and distal aortic neck lengths and total distance from the lower renal artery to the higher iliac bifurcation. Width measurements included proximal and distal neck diameters, maximum AAA diameter and common iliac diameters just above the iliac bifurcations. The measurements were performed in random order by two vascular surgeons, twice per method with 1-month interval between readings. In the CLL 3D-CTA method we used semi-automated CLL detection by software and manual measurements on CTA slices perpendicular to CLL. The equal measurements in 2D-CTA were performed manually on axial CTA slices using a DICOM viewer workstation. The intra- and interobserver variability, as well as the agreement between the two methods were assessed by Bland-Altman test and bivariate correlation analysis.

RESULTS

The intraobserver variability was significantly higher in 2D-CTA measurements for both readers. The interobserver variability was significant in 2D-CTA measurements of proximal neck dimensions while the agreement in CLL 3D-CTA analysis between the two readers was excellent in all studied parameters. The agreement between the two suitability analysis techniques was poor for both readers, especially in measurements of proximal neck's dimensions and in total aortoiliac length (p = 0.001).

CONCLUSION

In pre-EVAR morphological evaluation of AAAs the CLL-3D CTA post-imaging analysis has better intra- and interobserver correlation than 2D-CTA and might represent a useful tool for the proper selection of endograft's type and size.

Comparison between postprocessing techniques in the analysis of hepatic arteries using multi-detector-row computed tomography angiography

PURPOSE

Our purpose was to compare 4 different postprocessing techniques (maximum-intensity projection [MIP], multiplanar reconstruction, curved planar reconstruction, and volume rendering [VR]) for the study of hepatic arteries.

METHODS

One hundred thirty-seven patients who underwent multi-detector-row computed tomography angiography between August 2009 and January 2010 were retrospectively analyzed. For each patient and for each reconstruction method, the image quality was evaluated and the interobserver and intraobserver agreement was calculated according to Cohen statistics.

RESULTS

The Pearson r between the observers for the common hepatic artery measurement (Hounsfield unit) was good (r = 0.88). The VR showed a Cohen κ value of 0.78, and the highest image-quality score was obtained using MIP (total value, 384; mean value, 3.01) for observer 1 and using VR and MIP for observer 2 (mean value of 2.94).

CONCLUSIONS

Maximum-intensity projection and VR showed the optimal interobserver and intraobserver agreement and the highest quality scores and therefore should be used as postprocessing techniques when analyzing the hepatic arteries.

Are multiplanar reconstructions necessary in routine body computed tomography practice?: what is the published evidence?

OBJECTIVE

During computed tomography interpretation, some anatomical regions are optimally displayed in planes other than axial. The purpose of this review was to define best interpretative practice, by demonstrating through literature review and case demonstration the computed tomography applications that should routinely include multiplanar viewing of the volume.

CONCLUSIONS

Owing to multidetector-row computed tomography technology, multiplanar reconstructions not only have become realistic and reliable but also, in some clinical settings, have been shown to improve diagnostic accuracy and interpretation speed.