Color Doppler ultrasound versus CT angiography for DIEP flap planning: A randomized controlled trial.

BACKGROUND: Identifying relevant perforators is crucial in planning a deep inferior epigastric perforator (DIEP) flap. Color Doppler ultrasonography (CDU) has gained popularity for localizing perforators; however, current evidence on its efficiency is still inconclusive. This study aimed to compare the efficiency of CDU with that of computed tomography angiography (CTA) in localizing and selecting the relevant perforators. METHODS: In this randomized controlled trial, 60 patients undergoing DIEP flap breast reconstruction (uni- or bilateral) were randomly assigned to the CDU group (i.e., CDU was performed to map and select the relevant perforators preoperatively) or the CTA+CDU group (i.e., mapping was based on CTA and supplemented by CDU). CDU was performed by the same surgeon with a well-defined sonography experience from our previous study. The reference XY coordinates of the dissected perforators were measured intraoperatively, and deviations from preoperatively deducted coordinates were calculated (ΔCDU or ΔCTA+CDU). The flaps were categorized according to the number of dissected perforators, and adherence to the preoperative strategy was evaluated. RESULTS: Overall, 22 patients (30 flaps) in the CTA+CDU group and 27 (39 flaps) patients in the CDU group were evaluated. The average ΔCDU (0.6 cm) was significantly lower than the average ΔCTA+CDU (1.0 cm) (p < 0.001). Adherence to the mapping-based dissection strategy was higher in the CDU group; however, the difference was insignificant (p = 0.092). CONCLUSION: CDU is not inferior to CTA + CDU in localizing and selecting relevant DIEA perforators. Therefore, CDU mapping is a possible complementary or substitute modality for CTA mapping.

Description of Ore Particles from X-Ray Microtomography (XMT) Images, Supported by Scanning Electron Microscope (SEM)-Based Image Analysis.

In this paper, three-dimensional (3D) image data of ore particle systems is investigated. By combining X-ray microtomography with scanning electron microscope (SEM)-based image analysis, additional information about the mineralogical composition from certain planar sections can be gained. For the analysis of tomographic images of particle systems the extraction of single particles is essential. This is performed with a marker-based watershed algorithm and a post-processing step utilizing a neural network to reduce oversegmentation. The results are validated by comparing the 3D particle-wise segmentation empirically with 2D SEM images, which have been obtained with a different imaging process and segmentation algorithm. Finally, a stereological application is shown, in which planar SEM images are embedded into the tomographic 3D image. This allows the estimation of local X-ray attenuation coefficients, which are material-specific quantities, in the entire tomographic image.