A three-dimensional (3D) representation of pericardial cavity based on computed tomography (CT).

PURPOSE: The 3D modeling of human anatomy is more and more often used in medical education and in computer-augmented medicine. The lack of a 3D model of the pericardium has led us to its implementation. METHODS: The pericardium was reconstructed from a CT scan recording of a young, healthy subject. The anonymous CT scan data were blindly reviewed and interpreted by two independent radiologists. Stage one consisted in reconstructing the entire heart with the main afferent and efferent vessels. As the pericardial layers cannot be observed only with the CT scan, the second stage was to draw its reflection line following the most frequent model of pericardium defined in one of our prior studies. Afterwards, the epicardium had to be milled to finally create a pericardial sac area. RESULTS: Firstly, a model of one normal heart was reconstructed. Secondly, parietal and visceral layers of the pericardium have been achieved from the representation of their line of reflection. A short video shows recesses and sinuses and particularly, the transverse sinus crossed by a virtual object. CONCLUSIONS: The resulting model is subject to certain limits, including reproducibility linked to the operator, individual anatomical variation, and scanner resolution but it represents a pericardial pouch true to its more common anatomical morphology. It offers a very precise educational tool. It must be considered as the first step of an automatic segmentation and reconstruction process to modelize normal and pathological pericardium. This is also the first step before a 3D dynamic model, synchronized with heartbeats.

[Diagnosis, evolution and prognosis of prenatally diagnosed suprasellar cysts]. / Diagnostic, évolution et pronostic des kystes supra-sellaires de découverte anténatale.

Suprasellar arachnoid cysts (SAC) in children are considered rare, but the incidence is increasing due to the improvement of prenatal diagnosis. We present 15 cases of SAC diagnosed during the antenatal period between 2005 and 2015. The records were reviewed retrospectively by specifying the radiological characteristics, treatment modalities, outcomes, and long-term monitoring. Mean follow-up was 71 months. The forms (SAC-1) accounted for 2 cases (13%) with hydrocephalus. We observed 8 (53%) lower forms (SAC-2) with interpeduncular cistern expansion without hydrocephalus. The 5 (33.5%) remaining patients showed asymmetrical forms (SAC-3). Six patients (40%) were treated by ventriculo-cysto-cisternostomy, 1 by fetoscopy, 1 (6.5%) by ventriculo-peritoneal shunt, 2 (13.5%) by pterional craniotomy, and 6 (40%) were simply followed. The surgical outcomes were initially favorable in 9 cases (100%), 1 patient (13%) had to be re-treated later. Non-operated patients were all type 2 and showed no radiological changes. In the long-term, 1 patient (6.5%) had endocrine disruption, 1 had delayed development, 2 (13.5%) had minor neuropsychological impairments, and 1 had epilepsy. Combined monitoring with prenatal MRI and ultrasound can be used to distinguish three subtypes of SAC. SAC-1 and SAC-3 have an excellent prognosis after treatment in the perinatal period. SAC-2 can benefit from simple monitoring and remain asymptomatic in their majority. This classification allows a better prognosis estimation and better treatment decision.

[Trap in severe trauma: the rotary atlantoaxial dislocation]. / Piège en traumatologie : la luxation C1-C2.

We reported the case of asymptomatic traumatic atlantoaxial dislocation in a 14-year-old woman. Clinical diagnosis of this uncommon dislocation is difficult and often made late. The early diagnosis by CT scan is necessary to avoid secondary aggravation. Integrity of the transverse ligament of the atlas is a determining factor for atlantoaxial stability and allows orthopaedic treatment after reduction using moderate traction on the head.

Risk assessment of electromagnetic fields exposure with metallic orthopedic implants: a cadaveric study.

Metallic materials are well known to strongly interact with electromagnetic fields. While biological effects of such field have been extensively studied, only few works dealt with the interactions of electromagnetic waves with passive metallic device implanted in biological system. Hence only several numerical and phantom simulation studies were focusing on this aspect, whereas no in situ anatomic experiment has been previously performed. In this study the effect of electromagnetic waves on eight different orthopaedic medical devices (six plates from 55 to 318mm length, a total knee and a total hip prosthesis) were explored on six human cadavers. To mimic a random environmental exposure resulting from the most common frequencies band used in domestic environment and medical applications (TV and radio broadcasting, cell phone communication, MRI, diathermy treatment), a multifrequency generator emitting in VHF, UHF, GSM and GCS frequency bands was used. The different medical devices were exposed to an electromagnetic field at 50W/m(2) and 100W/m(2). After 6min exposure, the temperature was measured on three points close to each medical device, and the induced currents were estimated. No significant temperature increase (<0.2°C) was finally detected; beside, a slight induced tension (up to 1.1V) was recorded but would appear too low to induce any biological side effect.