Valérie Bertaud

MRI Investigation of Radiating Pain in the Lower Limbs: Value of an Additional Sequence Dedicated to the Lumbosacral Plexus and Pelvic Girdle

OBJECTIVE In some cases, sciatica-like symptoms radiating through the buttock, anterior thigh, or leg result from spinal root compression in an extraspinal location or from injury to the pelvic girdle. It has been suggested that adding a coronal STIR sequence dedicated to the lumbosacral plexus and pelvis to the routine MRI protocol can provide a good depiction of disorders of this type. MATERIALS AND METHODS Two hundred nine patients with sciatica-like symptoms of suspected lumbar origin were included in the study. Disorders responsible for symptoms involving extraspinal compression of the lumbosacral plexus or pelvic girdle were retrospectively noted and correlated with age, sex, location of pain, referring physician, presence of discoradicular impingement liable to explain symptoms, and history of neoplasia. RESULTS An extraspinal cause of symptoms was depicted in 12 cases (5.7%), including three cases of extraspinal compression and nine differential diagnoses in the pelvic region. Prevalence of an extraspinal cause of pain was significantly correlated with the absence of discoradicular impingement in the spine (p=0.046). A higher prevalence of extraspinal compression of the lumbosacral plexus (p=0.029) was seen in patients 60 years old or older, whereas no other feature was statistically associated with an extraspinal cause of pain. CONCLUSION Because of its short acquisition time and subsequent low cost, the additional coronal STIR sequence should be performed in the routine MRI investigation of sciatica-like symptoms when no discoradicular impingement is seen in the spine to depict an extraspinal cause of symptoms.

The value of using verbs in Medline searches.

New findings are continuously identified thanks to novel diagnostic procedures, among others in medical imaging. It would be useful to retrieve these new findings from literature. The aim of this work is to investigate if using verbs in MEDLINE queries can improve the retrieval of findings. Verbs used in the field of findings were selected: ‘to show’ (an examination shows a finding) and ‘to confirm’ (a finding confirms a diagnosis). For each of these verbs, semantically close verbs were researched on the WordNet website. Then, the extent to which adding these verbs to a query about various radiological pathologies can improve findings retrieval in Medline citations was studied. This method has been tested on two sets of MEDLINE citations regarding the diagnostic imaging of musculo-skeletal disorders. Using appropriate verbs in Medline queries enhances the precision from 53% to 61% and from 53% to 74%, respectively, in our first and second test set. A recall of 74% and 83% was reached in our two experiments. Using relevant verbs can be a rather simple way to improve the retrieval of findings related to diseases and diagnostic procedures from Medline citations.

L’informatisation du signe radiologique

The goal of this article is to present to the radiologist the different theories of the sign and their consequences for sign representation in computer systems. All the theories of the sign are presented, but the most relevant are highlighted in order to explain the great modeling systems currently in use (such as DICOM-SR or the UMLS). The constructivist approach of the notion of disease, the semiosis process, which starting from signs produces new signs, and the structuralist analysis of sign through language are emphasized. The purpose of this analysis is to end up with a consensual representation of the sign that can be understood by human beings and processed by machines. Such a representation, also known as an ontology, is based on a semantic organization of language, thus allowing medicine to become a truly scientific discipline. It aims at disambiguating the symbols given to machines, which will help us in our reasoning.

Prise en compte de la forme des dents dans un contexte d’hyperdivergence faciale

INTRODUCTION The study examines how the shape of the teeth is taken into account in the context of facial hyperdivergency. One aim was to check out the widely-held belief that the hyperdivergent patient has long teeth. DISCUSSION Our study found no link between the shape of the teeth and facial hyperdivergency, thus confirming the results in the literature. We examined the issue of how to characterize dental shapes. We found three diversely-appreciated types of shape: rectangular, triangular and ovoid. Individualized management of tooth shape harmony enables the clinician to envisage recontouring the shape of a patients teeth using interproximal enamel reduction. The anatomical demands of this type of tooth remodeling favor the less popular ovoid and triangular shapes. However, following treatment, they tend to adopt a more widely-accepted rectangular shape. MATERIALS AND METHODS Using a spreadsheet, we built a computational tool to perform the dimensional quantitative diagnosis and made drawings in order to approach the shapes from a qualitative point of view. This method enables us to determine the areas to be recontoured and to obtain a preview of our treatment objectives. The result is harmonious with respect to shapes, proportions and positions as well as from a functional and periodontal point of view.

Relations entre les extractions de dents de sagesse et les dysfonctionnements de l'appareil manducateur: étude cas/témoins [Relations between extraction of wisdom teeth and temporomandibular disorders: a case/control study]

The aim of this study was to assess the impact of extraction of third molars on the occurrence of temporo-mandibular disorders (TMD). A review of the literature and a case-control study have been conducted. The case-control study compares the frequency of extraction of third molars between the sample with TMD (case) and the sample without TMD (control). The proportion of patients who had undergone extractions of wisdom teeth was higher in the case group than in the control group. The difference was statistically significant when patients had undergone extraction of all four wisdom teeth or when the extraction of four wisdom teeth underwent in one sitting or under general anesthesia. The study of patients in case sample shows that all signs of TMD were more common in patients who had undergone extractions in several sessions and under local anesthesia. The temporomandibular joint sounds are significantly more frequent with local anesthesia. In the case group, 85 to 92% of patients have parafunctions and 5 to 11% have malocclusion. This demonstrates the multifactorial etiology of temporomandibular disorders.

Vers une representation unifiee de la semiologie en imagerie medicale

Objectifs Proposer une representation unifiee de la semiologie en imagerie medicale integrant les differentes representations existantes : comptes rendus (DICOM Structured Reporting (DICOM SR)), articles medicaux (Mesh et Medline) et les ressources d’enseignement (« GAMUTS in radiology » de Reeder et Felson (GAMUTS)). Materiels et methodes Apres avoir analyse la representation de la semiologie dans DICOM SR, « l’Unified Medical Language System Semantic Network » (UMLS) et le GAMUTS, nous avons reecrit les phrases de semiologie du GAMUTS avec la terminologie de l’UMLS et la syntaxe de DICOM SR. Resultats L’analyse des systemes montre que l’UMLS donne la valeur semantique des termes de semiologie qui peut etre augmentee par la syntaxe fournie par DICOM SR. L’utilisation de ces deux modes de representation permet de reecrire les phrases de semiologie du GAMUTS suivant une representation unifiee. Conclusion La semiologie radiologique est un element central du discours medical. Sa representation « academique » presente dans le GAMUTS n’est pas celle proposee par DICOM SR ni celle de la modelisation conceptuelle des ontologies. L’interet de ce travail est de montrer qu’il est possible d’unifier ces trois representations.

Methode de creation de bases de connaissances radiologiques utilisant le test de concordance des scripts

Objectifs Proposer et evaluer une methode de creation d’une base de connaissances radiologiques centree sur les plaintes des patients utilisant le test de concordance des scripts. Materiels et methodes Nous utilisons la methode d’elaboration des scripts pour interroger des experts sur les scapulalgies. Ils creent des items : indications (si je pense faire – et qu’alors je trouve – l’effet sur la necessite de demander cet examen est) et diagnostics (si je pense a – et qu’alors je trouve – l’effet sur l’hypothese diagnostique est). Les items obtenus sont ensuite relies comme suit : signe d’appel (indique) examen (montre) signe radiologique (diagnostique) maladie. L’analyse globale des relations a ensuite ete effectuee. Resultats Le reseau semantique est constitue de 131 chainons diagnostics et 89 chainons indications. Les chainons indications sont constitues de 20 examens et de 59 signes d’appel. Les chainons diagnostics sont constitues de 55 diagnostics et 72 signes radiologiques. Le reseau se replie car maladies, signes d’appel et signes radiologiques peuvent partager les memes concepts. Conclusion Le test de concordance des scripts permet d’interroger les experts en suivant leur logique hypotheticodeductive. Le reseau semantique obtenu est une modelisation du processus d’indication et de diagnostic radiologique. Il est utilisable pour des tâches automatisees d’evaluation ou d’expertise.