# Preoperative Planning for Superior Messetric Artery Aneurysm
## 2 Materials and Methods  
First, the radiologist must identify and characterize the SMA aneurysms, to allow the vascular interventional radiologist or vascular surgeon to choose the appropriate treatment. A true aneurysm is formed when all three layers are weakened and dilatation of at least 1.5 times the normal diameter is observed. At the same time, a pseudoaneurysm is usually caused by vessel injury; this is the collection of blood between one or two layers and the adjacent parenchyma. It is easy to detect large SMA aneurysms on axial section images. However, in the case of small aneurysms, MPR, maximum intensity projection, and 3D-rendered images are the best choice for visualization. In the CT angiographic report, the SMA aneurysms would be described as saccular or fusiform. In this case, the artery should be inspected carefully to identify a concomitant dissection. Peripheral low attenuation within the aneurysm sac is seen with a mural thrombus. It was observed that true aneurysms have continuous wall calcifications and are often incidental. As for the pseudoaneurysms, they usually manifest symptomatically and can be caused by tumor erosion, trauma, or inflammation. Findings on CT images include extensive mural thrombus, adjacent hemorrhage, and discontinuous wall calcification. Inflammatory fat stranding can be seen near a pseudoaneurysm in patients with pancreatitis. Important information about the aneurysm's location, size, branch vessel involvement, the presence of rupture, and collateral vessel circulation is provided via multidetector CT scans. Vascular surgeons and/or interventional radiologists and/or GI surgeons are involved in mesenteric artery aneurysm cases. Sometimes, for patients with acute abdominal pain, a single venous phase scan is performed as SMA abnormalities may not be suspected. However, this does not mean that it is not possible to evaluate the SMA because the spatial resolution of current-generation multidetector CT scanners enables the identification of SMA abnormalities in the venous phase if the artery is inspected carefully in all imaging planes [13]. When an acute SMA abnormality is suspected, narrow detector sections (<1 mm), thin reconstruction sections (3 mm for axial images and 0.75 mm for two- or three-dimensional (2D or 3D) rendering), rapid infusion of intravenous contrast material (5 mL/s), and imaging in the arterial and venous phases are necessary to identify lesions in the SMA and to characterize the extent of vascular, gastrointestinal, and mesenteric complications. Post-processed sagittal and coronal two-dimensional multiplanar reformations (MPRs) should be rendered routinely, and 3D rendering at an independent workstation facilitates identification and characterization of SMA abnormalities that are missed on axial images, particularly in the more distal branches. The celiac and SMA origins should be inspected on sagittal MPR images, and the distal branches of the SMA should be examined on coronal MPR images [13]. The first major branch of the SMA is the inferior pancreaticoduodenal artery. Within the mesenteric root, the SMA branches into approximately four to six jejun and nine to 13 ileal arteries arising on the left side. The right-sided branches include the middle colic, right colic, and ileocolic arteries. The branching pattern of the colonic arteries often varies. All these blood vessels should be investigated carefully on CT angiographic images. We used an in-house custom-made platform named CardioCTNav in order to investigate all these anatomical details and to perform surgery planning. CardioCTNav is a cross-platform (Linux, macOS, Windows) in-house medical imaging software application based on open-source technologies--C++ programming language, Qt [14], VTK [15], DICOM for VTK [16], CTK [17]. It is a fast and stable solution, easy to learn and to use, developed by authors and offering them complete control over the implementation of the protocol described in the following sections.