Somatom 64

Perforator vessels were measured in all experimental animals via MDCT angiography using a 64-detector scanner (Somatom® 64, Siemens, Germany) with 1 mm slice thickness. Perforator and pedicle caliber measurements were performed on maximum-intensity-projection images in each animal for all perforator flaps. All vessel dimensions are expressed as mean + standard deviation (STDEV). Three-dimensional volume-rendering (3D-VRT) provided a 3D-model for flap localization (see S1 Video, 3D-VRT pig vascular network model and perforator flaps localization).

CT examinations were indicated by clinical needs in all cases. All patients were examined with a 64-row CT scanner (Somatom 64, Siemens AG, Erlangen, Germany; collimation 0.6 mm). From the raw data, sagittal images with a slice thickness of 3 mm and an increment of 3 mm were reconstructed utilizing a sharp (bone) kernel (70f). These images were present in the initial reading and were reevaluated.

Image acquisition of the supra-aortic vessels was obtained with a 64-multi-detector-row CT system (Somatom 64, Siemens, Erlangen, Germany) using a routine imaging protocol. CTA measurements (including reference area, RA; minimal lumen area, MLA and area stenosis AS) were performed by agreement of 2 senior radiologists with > 20 years and > 15 years of experience in reporting carotid CTA.

All interventions were performed on a 64-slice (Siemens SOMATOM 64; Siemens Healthineers, Erlangen, Germany) or on a 128-slice (Siemens SOMATOM Definition AS+/Siemens SOMATOM Definition Edge) CT scanner, respectively. Each patient underwent a pre-interventional CT scan to examine the exact position and size of the fluid collection. The most suitable access path for the percutaneous drainage was planned on these images. Drainage catheters with different diameters (Flexima^®, Boston Scientific Corporation, Marlborough, MA, USA and ReSolve^®, Merit Medical, South Jordan, UT, USA; respectively) were used depending on the access path and the experience of the interventionalist. An unenhanced follow-up CT scan was performed immediately after drainage catheter placement to evaluate the outcome of the intervention with respect to the position of the drainage and potential peri-interventional complications. No contrast media was administered. Images were reconstructed using a soft tissue convolution kernel at a slice thickness of 3 mm.

Neuroimaging in both hospitals was performed on a fourth-generation computed tomography (CT) scanner (Somatom 64, Somatom Definition AS+, Siemens Healthcare, Erlangen). Each CT scan consisted of 10–12 slices at a thickness of 4.8 mm for the skull base; 10–12 slices at a thickness of 7.2 mm for the cerebrum (Somatom 64); 22–25 slices at a thickness of 4.8 mm for the entire brain (Somatom AS+); or a multi-slice spiral CT data set. CT images were acquired in the orbito-meatal plane. For analysis, the absolute ICH and PHE volumes were obtained using a validated semi-automatic volumetric algorithm as previously described, with a high level of inter/intra-rater reliability. A threshold of 5–33 Hounsfield Units was used for calculating PHE volume. All measurements were performed by B.V (23 (link)). Midline shift was assessed by measuring the distance (mm) between the third ventricle and a designated midline drawn between the anterior and posterior attachments of the falx to the inner table of the skull. For better temporal comparison, the different time points of the CT scans were merged into time clusters (days 1, 2–3, and 4–7). All CT scans were included for analysis, especially for the purposes of assessing hematoma expansion. Hematoma volume, PHE volume, and midline shift were also recorded.