Y. Renard

A guide for effective anatomical vascularization studies: useful ex vivo methods for both CT and MRI imaging before dissection

The objective of this study was to develop a simple and useful injection protocol for imaging cadaveric vascularization and dissection. Mixtures of contrast agent and cast product should provide adequate contrast for two types of ex vivo imaging (MRI and CT) and should harden to allow gross dissection of the injected structures. We tested the most popular contrast agents and cast products, and selected the optimal mixture composition based on their availability and ease of use. All mixtures were first tested in vitro to adjust dilution parameters of each contrast agent and to fine‐tune MR imaging acquisition sequences. Mixtures were then injected in 24 pig livers and one human pancreas for MR and computed tomography (CT) imaging before anatomical dissection. Colorized latex, gadobutrol and barite mixture met the above objective. Mixtures composed of copper sulfate (CuSO4) gadoxetic acid (for MRI) and iodine (for CT) gave an inhomogeneous signal or extravasation of the contrast agent. Agar did not harden sufficiently for gross dissection but appears useful for CT and magnetic resonance imaging (MRI) studies without dissection. Silicone was very hard to inject but achieved the goals of the study. Resin is particularly difficult to use but could replace latex as an alternative for corrosion instead of dissection. This injection protocol allows CT and MRI images to be obtained of cadaveric vascularization and anatomical casts in the same anatomic specimen. Post‐imaging processing software allow easy 3D reconstruction of complex anatomical structures using this technique. Applications are numerous, e.g. surgical training, teaching methods, postmortem anatomic studies, pathologic studies, and forensic diagnoses.

Unraveling Pancreatic Segmentation

BackgroundLimited pancreatic resections are increasingly performed, but the rate of postoperative fistula is higher than after classical resections. Pancreatic segmentation, anatomically and radiologically identifiable, may theoretically help the surgeon removing selected anatomical portions with their own segmental pancreatic duct and thus might decrease the postoperative fistula rate. We aimed at systematically and comprehensively reviewing the previously proposed pancreatic segmentations and discuss their relevance and limitations.MethodsPubMed database was searched for articles investigating pancreatic segmentation, including human or animal anatomy, and cadaveric or surgical studies.ResultsOverall, 47/99 articles were selected and grouped into 4 main hypotheses of pancreatic segmentation methodology: anatomic, vascular, embryologic and lymphatic. The head, body and tail segments are gross description without distinct borders. The arterial territories defined vascular segments and isolate an isthmic paucivascular area. The embryological theory relied on the fusion plans of the embryological buds. The lymphatic drainage pathways defined the lymphatic segmentation. These theories had differences, but converged toward separating the head and body/tail parts, and the anterior from posterior and inferior parts of the pancreatic head. The rate of postoperative fistula was not decreased when surgical resection was performed following any of these segmentation theories; hence, none of them appeared relevant enough to guide pancreatic transections.ConclusionCurrent pancreatic segmentation theories do not enable defining anatomical–surgical pancreatic segments. Other approaches should be explored, in particular focusing on pancreatic ducts, through pancreatic ducts reconstructions and embryologic 3D modelization.

A radio-anatomical correlation study of the cisterna chyli

Surgical laparoscopic procedures in the retroperitoneal and supramesocolic spaces are increasingly frequent. There is a high risk of iatrogenic intraoperative injury of the retroperitoneal lymphatic structures during these procedures. A precise understanding of the anatomy of the thoracic duct (TD) and the cisterna chyli (CC) is essential for safe surgical procedures in this area. However, routine imaging procedures rarely and often incorrectly visualize the CC. The objective of this study was to evaluate the feasibility of a retrograde injection of the TD to fill the CC with a contrast agent in 16 human cadavers. Both magnetic resonance lymphography (MRI) and computed tomography (CT) studies could be performed on the same anatomical specimen, using a contrast medium which hardened, allowing gross dissection. MRI and CT detectability were evaluated, and imaging results were compared with the anatomical dissection. The CC of 12/16 cadavers were successfully injected, and four were unsuccessful due to technical difficulties, showing the effectiveness of the method. This technique can improve understanding of the anatomy of the TD and CC and provides an original option to study the complex anatomy of these structures by correlating precise cadaveric dissections with cross‐sectional imaging.

Aide de l’informatique à l’enseignement : exemple de l’anatomie sectionnelle du crâne et de la face

Objectifs du CD-ROM ce CD-ROM a pour but l’enseignement de l’anatomie sectionnelle du crâne et de la face. Il utilise pour cela des coupes axiales scannographiques et anatomiques d’une tete, numerisees et de haute qualite. Chaque planche est visualisable avec et sans legendes. Il est dote d’une interface conviviale comprenant deux modes : un mode « enseignement », ou les deux types de coupes sont accessibles sans et avec les legendes. Des calques des structures osseuses, musculaires, et vasculaires sont aussi superposables sur les coupes anatomiques, un mode « jeu », ou l’ordinateur propose a l’etudiant pour une planche donnee de repondre a des QCM portant sur les differentes structures que le programme designe. Conclusion ce CD-ROM est destine aux etudiants en Medecine comme initiation a l’imagerie du crâne et de la face. Il sera prochainement accessible en telechargement direct sur le site du laboratoire d’Anatomie de la Faculte de Medecine de Reims.