Atypical, unusual, and misleading imaging presentations of spondylolysis

Abstract

Although lumbar spondylolysis is a widely known and easily recognizable condition in its typical presentation, there are some less well-known forms that may occasionally be challenging and/or demand special attention on imaging. Examples include: acute and/or incomplete lesions; unilateral defects; lesions at unusual levels (cervical, upper lumbar, and multi-level spondylolyses); iatrogenic lesions; non-isthmic spondylolysis; and spondylolysis related to underlying diseases. In addition to their atypical, uncommon or confusing imaging presentations, these forms of spondylolysis are far rarer than the classic type and have been described, to a great extent, in the surgical literature, thus reducing the awareness of radiologists about them and raising the potential for misdiagnosis and inadequate treatment. In this review the authors address these special manifestations of spondylolysis, stressing the more important features to be considered in the differential diagnosis and the impact of a precise diagnosis of spondylolysis on the patient's care.

Working Towards a BDI‑Agent Based on Personality Traits to Improve Normative Conflicts Solution

“…Finally, Viana et al [1] presents a modeling language and an architecture to build adaptive normative agents. The authors propose an approach to design and implement agents that are capable to adapt in order to deal with norms, detecting and overcoming normative conflicts.…”

“…This section describes some related work: (i) the solution for normative conflicts [1], [8], [15], [16]; (ii) architecture designs considering the agent's emotional state [14], and (iii) the agent's personality [5].…”

“…Some approaches [1], [8], [15], [16] have been proposed in the literature to develop the agent that evaluates the effects of solving normative conflicts. For instance, the n-BDI architecture defined by Criado et al [15] presents a model for building environments governed by norms.…”

“…Multi-agent Systems (MASs) are societies in which these heterogeneous and individually designed entities (agents) work to accomplish common or independent goals [1]. In order to deal with autonomy and diversity of interests among the different members, such systems provide a set of norms, which are mechanisms used to restrict the behavior of agents by defining what actions the agents are obligated, permitted, or prohibited to encourage the fulfillment of the norm through rewards definition and discouragement of norm violation by pointing out the punishments [2].…”

“…The decision-making process about which norms will be fulfilled or violated might be defined based on the agent's goals, rewards and punishment analysis [1]. Since an agent's priority is the satisfaction of its own goals, before complying with norms, the agent must evaluate their positive and negative effects on its goals [3] without hurting the agent's autonomy.…”