Philippe Decq

Hôpital Henri Mondor (Hôpitaux Universitaires Henri Mondor), Créteil, Île-de-France, France

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Publications (118)224.13 Total impact

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    ABSTRACT: Cerebrospinal fluid imaging plays a significant role in the clinical diagnosis of brain disorders, such as hydrocephalus and Alzheimer's disease. While three-dimensional images of cerebrospinal fluid are very detailed, the complex structures they contain can be time-consuming and laborious to interpret. This paper presents a simple technique that represents the intracranial cerebrospinal fluid distribution as a two-dimensional image in such a way that the total fluid volume is preserved. We call this a volumetric relief map, and show its effectiveness in a characterization and analysis of fluid distributions and networks in hydrocephalus patients and healthy adults. (accepted)
    Computerized Medical Imaging and Graphics 09/2015; 44:26-40. DOI:10.1016/j.compmedimag.2015.06.001 · 1.50 Impact Factor
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    Dataset: science
    Amir Nakib, Patrick Siarry, Philippe Decq
  • Annals of Physical and Rehabilitation Medicine 05/2014; 57:e19-e20. DOI:10.1016/j.rehab.2014.03.066
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    ABSTRACT: To develop automated deformation modelling for the assessment of cerebrospinal fluid (CSF) local volume changes in patients with hydrocephalus treated by surgery. Ventricular and subarachnoid CSF volume changes were mapped by calculating the Jacobian determinant of the deformation fields obtained after non-linear registration of pre- and postoperative images. A total of 31 consecutive patients, 15 with communicating hydrocephalus (CH) and 16 with non-communicating hydrocephalus (NCH), were investigated before and after surgery using a 3D SPACE (sampling perfection with application optimised contrast using different flip-angle evolution) sequence. Two readers assessed CSF volume changes using 3D colour-encoded maps. The Evans index and postoperative volume changes of the lateral ventricles and sylvian fissures were quantified and statistically compared. Before surgery, sylvian fissure and brain ventricle volume differed significantly between CH and NCH (P = 0.001 and P = 0.025, respectively). After surgery, 3D colour-encoded maps allowed for the visual recognition of the CSF volume changes in all patients. The amounts of ventricle volume loss of CH and NCH patients were not significantly different (P = 0.30), whereas readjustment of the sylvian fissure volume was conflicting in CH and NCH patients (P < 0.001). The Evans index correlated with ventricle volume in NCH patients. 3D mapping of CSF volume changes is feasible providing a quantitative follow-up of patients with hydrocephalus. • MRI can provide helpful information about cerebrospinal fluid volumes. • 3D CSF mapping allows quantitative follow-up in communicating and non-communicating hydrocephalus. • Following intervention, fissures and cisterns readjust in both forms of hydrocephalus. • These findings support the hypothesis of suprasylvian block in communicating hydrocephalus. • 3D mapping may improve shunt dysfunction detection and guide valve pressure settings.
    European Radiology 01/2014; 24(1):136-142. DOI:10.1007/s00330-013-2990-z · 4.34 Impact Factor
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    ABSTRACT: The objective of this study was to quantify in spastic lower limbs the changes in reflex EMGs and in ankle stiffness after a lidocaine block of the soleus nerve to better understand physiological effects of lidocaine. Twenty patients were prospectively included and assessed before and after lidocaine block of the soleus nerve. We studied clinical and neuromechanical parameters of the triceps surae, including quantification of the maximum Hoffmann's reflex (Hmax) and tendinous reflex (T) normalized to the maximum direct motor response (Mmax), and passive ankle stiffness assessed by sinusoidal length perturbations. All patients whatever the aetiology of spasticity were improved in clinical parameters of spasticity after the block (62% reduction of the Ashworth score, 85% reduction of stretch reflex scores, increased score on the Physicians' Rating Scale). All patients presented a reduction of the Hmax-Mmax ratio (mean reduction of 67%) and the T-Mmax ratio (82%). Ankle stiffness was decreased by an average of 23%. Measured stiffness was correlated with the Ashworth score and the T-Mmax ratio. Relatively greater change in the T reflex than in the H reflex suggests that lidocaine block reduces hyperreflexia not only by interfering with generation of afferent volleys in the injected nerve, but also probably by altering generation of the volleys at the level of muscle spindles in the affected spastic muscles, presumably by blocking the transmission along gamma-efferent fibers.
    Applied Physiology Nutrition and Metabolism 11/2013; 38(11):1120-7. DOI:10.1139/apnm-2013-0070 · 2.01 Impact Factor
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    ABSTRACT: Purpose: Medical image visualization is an important step in the medical diagnosis of hydrocephalus. In this paper, we present planar representations called volumetric relief maps that are generated from three-dimensional images of the cerebrospinal fluid within the cortical subarachnoid space. Such maps are visually interpreted at once and allow to automatically characterize fluid distributions. Consequently, they help specialists to provide a diagnosis and to monitor patients instantly. Methods: Volumetric relief maps are generated by enclosing the cortical subarachnoid space with a hemisphere, and using a ray tracing method and a map projection technique from a hemisphere to a plane. Results: Visualization of maps indicates that healthy adults have more balanced fluid distributions with well-filled sulci, unlike hydrocephalus patients who have more or less large fluid depletions in the posterior regions of the brain. We showed that a moment-based approach allows to efficiently characterize such fluid distributions from maps. In particular, the center of mass of a distribution is an efficient discriminant factor to distinguish between healthy adults and hydrocephalus patients, with resulting sensitivity and specificity of 100%. In addition, we have noted that asymmetry of the fluid distribution increases with depletion for hydrocephalus patients; such asymmetry is generally oriented towards the frontal part of the fissura longitudinalis cerebri. Conclusions: This paper describes an innovative visualization tool used to analyze fluid distribution within the cortical subarachnoid space. It allows to efficiently discriminate between healthy adults and pathological cases, and to monitor patients before and after surgery.
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    ABSTRACT: Aims. In spastic subjects, lidocaine is often used to induce a block predictive of the result provided by subsequent surgery. Lidocaine has been demonstrated to inhibit the Hoffmann (H) reflex to a greater extent than the direct motor (M) response induced by electrical stimulation, but the timecourse of these responses has not been investigated. Methods. An animal (rat) model of the effects of lidocaine on M and H responses was therefore developed to assess this time course. M and H responses were recorded in 18 adult rats before and after application of lidocaine to the sciatic nerve. Results. Two to five minutes after lidocaine injection, M responses were markedly reduced (mean reduction of 44%) and H reflexes were completely abolished. Changes were observed more rapidly for the H reflex. The effects of lidocaine then persisted for 100 minutes. The effect of lidocaine was therefore more prolonged on the H reflex than on the M response. Conclusion. This study confirms that lidocaine blocks not only alpha motoneurons but also Ia afferent fibres responsible for the H reflex. The authors describe, for the first time, the detailed time course of the effect of lidocaine on direct or reflex activation of motoneurons in the rat.
    The Scientific World Journal 08/2013; 2013:912716. DOI:10.1155/2013/912716 · 1.73 Impact Factor
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    ABSTRACT: Over the last decade, endoscopic intraventricular and skull base operations have become widely used for a variety of evolving indications. The authors performed a global survey of practicing endoscopic neurosurgeons to characterize patters of usage regarding endoscopy equipment, instrumentation, and the indications for using image-guided surgery systems (IGSS). An online survey consisting of 8 questions was completed by 235 neurosurgeons with endoscopic surgical experience. Responses were entered into a database and subsequently analyzed. The median number of operations performed per year by intraventricular and skull base endoscopic surgeons was 27 and 25, respectively. Data regarding endoscopic equipment brand, diameter, and length are presented. The most commonly reported indications for IGSS during intraventricular endoscopic surgery were: tumor biopsy/resection, intraventricular cyst fenestration, septostomy/pellucidotomy, endoscopic third ventriculostomy (ETV), and aqueductal stent placement. Intraventricular surgeons reported using IGSS for all cases in 16.6% and never in 24.4%. Overall, endoscopic skull base surgeons reported using IGSS for all cases in 23.9% and never in 18.9%. The most commonly reported indications for IGSS during endoscopic skull base operations were: complex sinus/skull base anatomy, extended approaches, and reoperation. Many variations and permutations for performing intraventricular and skull base endoscopic surgery exist worldwide. Much can be learned by studying the patterns and indications for using various types of equipment and operative adjuncts such as IGSS.
    World Neurosurgery 07/2013; 80(6). DOI:10.1016/j.wneu.2013.05.011 · 2.42 Impact Factor
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    ABSTRACT: Hydrocephalus is a neurological disorder that usually results from obstruction of the cerebrospinal fluid outflow in the ventricles or in the subarachnoid space. Magnetic resonance imaging offers a great deal of information to specialists in the clinical diagnosis and treatment processes of hydrocephalus. Recently we have proposed a new magnetic resonance imaging sequence that significantly highlights the cerebrospinal fluid and a segmentation method for its space volumes assessment. Those studies indicate us that the fluid distribution in the cortical subarachnoid space varies significantly, according to whether or not there is a pathology. However, visualization and analysis of the fluid distribution, particularly that of cortical sulci, remain difficult in three dimensions. This paper proposes a method to retrieve a two-dimensional relief map of the cerebrospinal fluid distribution in the upper cortical subarachnoid space from our three-dimensional images. We define the upper cortical subarachnoid space as the region located above the plane that passes through the anterior and the posterior commissures. The posterior commissure is located behind the top of the cerebral aqueduct that can be readily detected in our images. This new representation provides both qualitative and quantitative information on the fluid distribution that surrounds the brain.
    27th International Congress in Computer Assisted Radiology and Surgery (CARS); 06/2013
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    ABSTRACT: Intracranial dural arteriovenous fistulae with perimedullary venous drainage are unusual type of vascular brain malformations. Patients may present with a rapidly progressive ascending myelopathy associated with autonomic dysfunction, which can cause a misdiagnosis and delay the therapeutic management. These clinical signs must be quickly recognized to avoid a poor outcome. The authors report the case of a 60-year-old woman presenting with a progressive myelopathy due to a dural arteriovenous fistula with perimedullary venous drainage. The diagnosis was suspected on brain-spinal MRI and confirmed by brain arteriography visualizing the arteriovenous shunt in the middle segment of the superior petrous sinus. MRI showed edema in the medulla oblongata. The treatment was performed early by endovascular glue embolization of the arteriovenous shunt and of the origin of the vein. Brain arteriography and clinical follow-up, one month later, showed complete disappearance of the dural fistula and regression of clinical symptoms. MRI control showed the reduction of the brain stem edema. Because of the early pejorative prognosis of these kinds of fistulae, early diagnosis and treatment are needed.
    Neurochirurgie 06/2013; · 0.47 Impact Factor
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    ABSTRACT: OBJECTIVES: To evaluate the feasibility of imaging the entire cerebrospinal fluid (CSF) volume using the SPACE MR sequence. METHODS: The SPACE sequence encompassing the brain and spine was performed at 1.5 T in 12 healthy volunteers and 26 consecutive patients with hydrocephalus. Image contrast was estimated using difference ratios in signal intensity between CSF and its background. Segmentation of CSF was performed using geometrical features and a topological assumption of CSF shapes. Subarachnoid and ventricular CSF space volumes were assessed in volunteers and patients and linear discriminant analysis was performed. RESULTS: Image contrast was 0.94 between the CSF and the brain and 0.90 between the CSF and the spinal cord. According to the phantom study, the accuracy of CSF volume measurement was 98.5 %. A clear distinction between patients and healthy volunteers was obtained using the linear discriminant analysis. Significant linear regression was found in healthy volunteers between ventricular (Vv) and the whole subarachnoid CSF volume (Vs) with Vv = 0.083 Vs. CONCLUSIONS: Imaging of the entire CSF volume is feasible in healthy volunteers and patients with hydrocephalus. CSF volume can be obtained on a whole-body scale. This approach may be of use for the diagnosis and follow-up of patients with hydrocephalus. KEY POINTS : • MRI assessment of CSF volume is feasible in healthy volunteers/hydrocephalus patients. • CSF volume can be obtained on a whole-body scale. • The ratio of subarachnoid and ventricular CSF is constant in healthy volunteers. • CSF linear discriminant analysis can distinguish between patients and healthy volunteers. • Entire CSF volume imaging is useful for diagnosing and following hydrocephalus.
    European Radiology 06/2013; 23(6):1450-1458. DOI:10.1007/s00330-012-2732-7 · 4.34 Impact Factor
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    ABSTRACT: Les fistules durales intracrâniennes à drainage veineux périmédullaire représentent de très rares cas de malformations vasculaires cérébrales. Les patients peuvent présenter une myélopathie ascendante rapidement évolutive associée à une dysautonomie, pouvant être à l’origine d’une errance diagnostique, et retarder la prise en charge thérapeutique. Ces signes cliniques doivent être ainsi rapidement reconnus afin d’éviter une évolution péjorative. Les auteurs présentent le cas d’une patiente, âgée de 60 ans, admise en milieu neurochirurgical pour un syndrome médullaire évolutif, dû à une fistule durale intracrânienne à drainage veineux périmédullaire. Le diagnostic a été suspecté sur une IRM cérébro-médullaire, puis confirmé par une artériographie cérébrale visualisant le shunt artério-veineux sur tiers moyen du sinus pétreux supérieur au niveau de la tente du cervelet. L’IRM montrait une souffrance œdémateuse bulbaire. La prise en charge thérapeutique s’est effectuée, en urgence, par voie endovasculaire, par l’embolisation à la colle du shunt et du pied de veine. L’évolution initiale, et à un mois du traitement, a été parfaitement favorable, puisque le contrôle artériographique montre la régression complète de la fistule durale, et que la symptomatologie clinique s’est amendée. De même, l’IRM de contrôle montrait la nette diminution de l’œdème bulbaire. Du fait de l’évolution clinique rapide de ces types de fistules durales, une prise en charge diagnostique et thérapeutique, très précoce, s’avère nécessaire.
    Neurochirurgie 06/2013; 59(3):133–137. DOI:10.1016/j.neuchi.2013.04.009 · 0.47 Impact Factor
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    ABSTRACT: BACKGROUND: The neuromechanical consequences of tibial neurotomy have not been extensively studied. METHODS: Fifteen patients were evaluated before and after selective tibial neurotomy (after 2 months and after 15 months) by means of clinical, neurophysiological [tendon (T) reflexes, Hoffmann (H) reflexes and maximum motor response, Mmax] and mechanical parameters (passive stiffness of plantar flexors at the ankle). The neurotomy concerned the soleus (100 % of cases), gastrocnemius (20 % of cases), posterior tibial (60 % of cases) and flexor digitorum longus (47 % of cases) nerves. RESULTS: Neurotomy provided more than 90 % improvement of clinical spasticity scores, 20 % improvement of walking scores and the angle of passive dorsiflexion (APDF) of the ankle (mean angle: 7°), temporary reduction of the soleus Mmax (18 % at 2 months with return to the preoperative value at 15 months), and lasting reduction of the soleus Hmax/Mmax (68 % at 2 months, 78 % at 15 months) and T/Mmax (84 % at 2 months, 80 % at 15 months). M and H responses of the gastrocnemius (whether or not they were included in the neurotomy) were not modified, while T/Mmax decreased to the same degree as for soleus. Passive stiffness was lastingly decreased from 64.0 Nm/rad to 49.0 Nm/rad (2 months) and 49.5 Nm/rad (15 months). CONCLUSION: Selective tibial neurotomy of the soleus nerve induces long-term reduction of reflex hyperexcitability and passive stiffness of plantar flexors in spastic patients, with no lasting impairment of motor efferents. In parallel, it modifies the tendon reflexes of synergistic muscles (gastrocnemius) not concerned by the neurotomy.
    Acta Neurochirurgica 05/2013; 155(9). DOI:10.1007/s00701-013-1770-5 · 1.79 Impact Factor
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    ABSTRACT: In this paper we analyze volumes of the cerebrospinal fluid spaces for the diagnosis of hydrocephalus, which are served as reference values for future studies. We first present an automatic method to estimate those volumes from a new three-dimensional whole body magnetic resonance imaging sequence. This enables us to statistically analyze the fluid volumes, and to show that the ratio of subarachnoid volume to ventricular one is a proportionality constant for healthy adults (= 10.73), while in range [0.63, 4.61] for hydrocephalus patients. This indicates that a robust distinction between pathological and healthy cases can be achieved by using this ratio as an index.
    Computerized Medical Imaging and Graphics 04/2013; 37(3):224-233. DOI:10.1016/j.compmedimag.2013.03.005 · 1.50 Impact Factor
  • Philippe Decq
    World Neurosurgery 10/2012; 80(5). DOI:10.1016/j.wneu.2012.10.034 · 2.42 Impact Factor
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    Annals of Physical and Rehabilitation Medicine 10/2012; 55:e266. DOI:10.1016/j.rehab.2012.07.669
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    Annals of Physical and Rehabilitation Medicine 10/2012; 55:e268-e269. DOI:10.1016/j.rehab.2012.07.676
  • Annales d Endocrinologie 09/2012; 73(4):305. DOI:10.1016/j.ando.2012.07.243 · 0.66 Impact Factor

Publication Stats

1k Citations
224.13 Total Impact Points

Institutions

  • 1989–2014
    • Hôpital Henri Mondor (Hôpitaux Universitaires Henri Mondor)
      • Service de Dermatologie
      Créteil, Île-de-France, France
  • 2009–2011
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 2008–2011
    • Université Paris-Est Créteil Val de Marne - Université Paris 12
      Créteil, Île-de-France, France
  • 2010
    • Hôpital Albert Chenevier – Hôpitaux Universitaires Henri Mondor
      Créteil, Île-de-France, France
  • 2004–2007
    • Assistance Publique – Hôpitaux de Paris
      Lutetia Parisorum, Île-de-France, France
  • 1995
    • University of Tours
      Tours, Centre, France