High-resolution CT Datasets Research Articles

Re-interpreting mesenteric vascular anatomy on 3D virtual and/or physical models, part II: anatomy of relevance to surgeons operating splenic flexure cancer

BackgroundThe splenic flexure is irrigated from two vascular areas, both from the middle colic and the left colic artery. The challenge for the surgeon is to connect these two vascular areas in an oncological safe procedure.Materials and methodsThe vascular anatomy, manually 3D reconstructed from 32 preoperative high-resolution CT datasets using Osirix MD, Mimics Medical and 3-matic Medical Datasets, were exported as STL-files, video clips, stills and supplemented with 3D printed models.ResultsOur first major finding was the difference in level between the middle colic and the inferior mesenteric artery origins. We have named this relationship a mesenteric inter-arterial stair. The middle colic artery origin could be found cranial (median 3.38 cm) or caudal (median 0.58 cm) to the inferior mesenteric artery. The lateral distance between the two origins was 2.63 cm (median), and the straight distance 4.23 cm (median). The second finding was the different trajectories and confluence pattern of the inferior mesenteric vein. This vein ended in the superior mesenteric/jejunal vein (21 patients) or in the splenic vein (11 patients). The inferior mesenteric vein confluence could be infrapancreatic (17 patients), infrapancreatic with retropancreatic arch (7 patients) or retropancreatic (8 patients). Lastly, the accessory middle colic artery was present in ten patients presenting another pathway for lymphatic dissemination.ConclusionThe IMV trajectory when accessible, is the solution to the mesenteric inter-arterial stair. The surgeon could safely follow the IMV to its confluence. When the IMV trajectory is not accessible, the surgeon could follow the caudal border of the pancreas.Graphical abstract

Soft 3D-Printed Phantom of the Human Kidney with Collecting System

Organ models are used for planning and simulation of operations, developing new surgical instruments, and training purposes. There is a substantial demand for in vitro organ phantoms, especially in urological surgery. Animal models and existing simulator systems poorly mimic the detailed morphology and the physical properties of human organs. In this paper, we report a novel fabrication process to make a human kidney phantom with realistic anatomical structures and physical properties. The detailed anatomical structure was directly acquired from high resolution CT data sets of human cadaveric kidneys. The soft phantoms were constructed using a novel technique that combines 3D wax printing and polymer molding. Anatomical details and material properties of the phantoms were validated in detail by CT scan, ultrasound, and endoscopy. CT reconstruction, ultrasound examination, and endoscopy showed that the designed phantom mimics a real kidney’s detailed anatomy and correctly corresponds to the targeted human cadaver’s upper urinary tract. Soft materials with a tensile modulus of 0.8–1.5 MPa as well as biocompatible hydrogels were used to mimic human kidney tissues. We developed a method of constructing 3D organ models from medical imaging data using a 3D wax printing and molding process. This method is cost-effective means for obtaining a reproducible and robust model suitable for surgical simulation and training purposes.

Satan's skeleton revealed: a tomographic and comparative osteology of Satan eurystomus, the subterranean Widemouth Blindcat (Siluriformes, Ictaluridae)

The Widemouth Blindcat, Satan eurystomus Hubbs and Bailey 1947, was the second of four stygobitic species of Ictaluridae discovered in the subterranean waters of southern Texas and northeastern Mexico. The skeletal anatomy of Satan has been scarcely known from a few, dated radiographs. Using additional radiographs and high resolution CT-datasets for two well-ossified specimens, we applied high-resolution X-ray computed tomography (HRXCT) to visualize, illustrate and describe the bony skeleton of Satan. We also provide an online archive of still and animated tomographic images of the skeletal anatomy of this little-known species.The skeleton and soft anatomy of Satan are distinctive. Twelve skeletal autapomorphies are described that singularly distinguish Satan within Ictaluridae and, probably in combination, from all other catfishes. Some of these are reductive losses or simplifications of skull bones (e.g. loss of one infraorbital bone; reduced ornamentation of the pterotic bone) and joint complexity (e.g. simple overlapping frontal-lateral ethmoid articulation; loosely ligamentous interopercle-posterior ceratohyal joint). Some of the autapomorphies are anatomically and perhaps developmentally complex (e.g. a novel series of three midline joints closing a middle span of the posterior cranial fontanel; a deeply excavated temporal fossa and an unusually enlarged interhyal bone). The tiny dorsal-fin spinelet (first lepidotrich) of Satan has a novel peaked and twisted shape.Ten apparent and exclusive synapomorphies within Ictaluridae gathered from this and previous studies suggest that Satan and Pylodictis are closest relatives. Most of these are functionally related to prey detection and suction feeding: fusion of the symphyseal mandibular sensory pores and increase in the number of preoperculo-mandibular canal pores; depressed, flattened heads and wide transverse mouths; prominent posterior process of the lateral ethmoid alongside and below the frontal bone margin; vertical and blade-like supraoccipital posterior process; unique arrangement of the parasagittal and occipital muscleattachment crests on the skull roof; large triangular panel of integument within the operculum framed by the opercle, preopercle and interopercle bones; elongated posterior ceratohyal; and, form of the fourth supraneural and loss of its anterior nuchal plate.In contrast, 15 synapomorphies recovered by Arce-H. et al. 2016, are confirmed suggesting that Satan is one of the four stygobitic ictalurids comprising a “Troglobites” subclade within the family: (Trogloglanis, Satan, Prietella phreatophila, P. lundbergi). These features include three stygomorphic and reductive apomorphies that are exclusive within Ictaluridae: loss of fully developed eyes and pigmentation, and simplification of the fifth vertebra and its joint with the Weberian apparatus. Twelve other synapomorphies shown by the Troglobites are also apparent homoplasies of character states shared with various other ictalurids. These include reductive characters such as shortened lateral line canal, reduced infraorbitals and underdeveloped or incomplete ossifications of the pterotic, supraoccipital, hyoid arch bones and transcapular ligament. Also, the Troglobites and various other ictalurids have: an adnate adiposecaudal fin, foreshortened anterior cranial fontanelle, reduced ventral wings of the frontal bone, replacement of bone by cartilage in hypohyal joints; incompletely ossified transcapular ligament, and consolidation of some hypural bones.Completing a full morphological character dataset across the Troglobites has been impeded by incomplete specimen preparations and study of P. lundbergi and to a lesser extent, P. phreatophila and Trogloglanis.

Rib fractures at postmortem computed tomography (PMCT) validated against the autopsy

To evaluate the sensitivity of postmortem computed tomography (PMCT) in rib fracture detection validated against autopsy.Fifty-one forensic cases underwent a postmortem CT prior to forensic autopsy. Two image readers (radiologist and forensic pathologist) assessed high resolution CT data sets for rib fractures. Correct recognition rates (CRR), sensitivity and specificity values were calculated over all observations as well as individually for every rib and region. Additionally, for partial rib fractures the sensitivity of autopsy was calculated vice versa.3876 entries in each study protocol (autopsy, PMCT radiologist and PMCT forensic pathologist) were investigated. A total of 690 fractures (autopsy), 491 (PMCT and radiologist) and 559 (PMCT and forensic pathologist) were detected. The CRR was 0.85. Sensitivity and specificity of PMCT for rib fracture detection were 0.63 (0.58 radiologist, 0.68 forensic pathologist) and 0.97 (both readers 0.97), respectively. Low CRR and sensitivity values were obtained for antero-lateral fractures. Partial rib fractures were better detected by PMCT.PMCT has a rather low sensitivity for rib fracture detection when validated against autopsy and indicates that clinical CT may also demonstrate a reasonable number of false negatives. Partial rib fractures often remain undetected at autopsy.

AB0720 Monitoring of changes of size, shape and bone mineral density of bone erosions in high resolution ct datasets of patients with rheumatoid arthritis under treatment

BackgroundDiagnosis and monitoring of patients with rheumatoid arthritis (RA) is largely based on radiographs, therefore the sensitivity to detect small changes of bone erosions is limited. This is also true...

A subway map for the lungs: Planar occlusion-free visualization of the bronchial tree

High resolution CT datasets from multi-slice scanners allow the inspection of thetracheobronchial tree down to the smaller airways for diagnostic purposes (e.g. to inspectairway lumen and bronchial wall thickness). Using manual or automated segmentationmethods, the bronchial tree structure may be discernable down to hundreds of subsegmentsof higher generations. Linear projections (such as maximum intensity projections) of thedelicate three-dimensional tree lead to multiple occlusions (left figure), and make theinspection and navigation along specific airway paths cumbersome.The planar mapping is computed automatically for each automatically extractedindividual bronchial tree. It gives an overview of the bronchial tree in a single glance, isprintable (e.g. for the diagnostic report), allows to convey diagnostic CAD-information tothe reader through color-coding (e.g. anomalies in wall thickness or broncho-arterialdiameter ratios), and eases three-dimensional navigation through the bronchial tree (themap is bijectively linked to the 3D image volume).The suggested mapping is also applicable to show anomalies in the pulmonary arterialtree.Two possible approaches for automatic production of a non-intersecting topological mapping:multi-slice CT lung segmentation airway tree segmentation centerline extractionThe topological mapping (subway map) can aid the navigationthrough the bronchial tree. A mouse-click into the subway map willset the ortho-viewer to the corresponding true 3D-position, indicatethe position in the three-dimensional tree model, and show areformat of the selected airway location which is reformattedperpendicular to the local airway orientation .(a) At each bifurcation of generation i, the mappingbranches by an angle ± θ

Virtual bronchoscopy: Our early experience

Virtual bronchoscopy is one of the many new radiological scanning techniques that have been recently introduced. Virtual endoscopy, according to Ahlquist (Ahlquist and Johnson CD, Gastroenterology, 112, 1997, 2150) is a technique for visualizing interior cavities using computer graphic techniques. Virtual bronchoscopy generates 3D reconstructions of the human airway from high-resolution CT data sets of the chest and performs a simulated bronchoscopy. This method uses perspective surface or volume rendering to produce endoscope-like visualizations of the airway. Our early experience with this new investigative modality in cases of laryngeal and subglottic stenosis and intratracheal tumors is discussed.