Role of modern imaging technology in the implementation of pediatric cochlear implants.

Since 1989, 40 patients have received cochlear implants in our institution. Over the past 2 years, 17 children among these patients have undergone radiographic assessment combining magnetic resonance imaging (MRI) and high-resolution computed tomography (CT) scanning. Imaging is not essential, and is only used after assessment by a multidisciplinary team. However, the imaging results influence the choice of implant, and sometimes the side to be implanted. The first study is always CT, as it detects congenital abnormalities, and for children with a history of bacterial meningitis, it can detect signs of labyrinthine ossification that contraindicates or complicates cochlear implantation. These signs are not always visible with tomodensitometry, especially when fibrosis within the canal has not yet ossified. This examination also provides for postoperative confirmation of implant position in case of failure or complication. Over the past 3 years, MRI has been combined with tomodensitometry, especially with children having a history of meningitis. This examination provides a basis for evaluating the liquid nature of the labyrinth. A GE Signa 1.5-T unit was used by the authors, employing sequences of volumetric acquisition (steady state free precision with 1.5-mm image slices and an angle of 15 degrees to 35 degrees). Hence, modern imaging plays an important role when the decision to implant has already been made, particularly in the case of profoundly deaf children. We always use MRI in combination with a CT scanner in children with a history of meningitis.

[Role of modern imaging (tomodensitometry and MRI) in cochlear implantation in children]. / Place de l'imagerie moderne (tomodensitométrie et I.R.M.) dans l'implantation cochléaire chez l'enfant.

Since 1989, 40 patients have received implants in the O.R.L. ward of the Hôpital d'Enfants Armand Trousseau (Paris). Over the past 2 years, 17 children have undergone radiological assessment combining M.R.I. anf high resolution C.T scanning. Imagery is not the essential stage, and is only used after assessment by a multidisciplinary team. However, the imagery results influence the choice of implant, and sometimes the side to be implanted. C.T is always the first stage as it detects congenital abnormalities, and, for children with a history of bacterial meningitis, it can detect signs of labyrinthine ossification which contraindicate cochlear implantation. These signs are not always visible using tomodensitometry, especially when fibrosis within the canal has not yet ossified. This examination also provides for post-operative confirmation of implant position in case of failure or complication. Over the past 3 years, Magnetic Resonance Imagery has been combined with tomodensitometry, especially with children having a past medical history of meningitis. This examination provides a basis for evaluating the liquid nature of the labyrinth. A G.E. Sygna 1.5 T was used by the authors, employing sequences of volumetric acquisition (S.S.F.P. with 1.5 mm image slices and an angle of 15 to 35 degrees). Hence, modern imagery plays an important role when the decision to implant has already been taken, particularly in the case of profoundly deaf children. M.R.I. is always used in combination with a scanner in cases involving children with a past medical history of meningitis.

[Value of magnetic resonance imaging associated with x-ray computed tomography in the screening of residual cholesteatoma after primary surgery]. / Intérêt de l'imagerie par résonance magnétique couplée a la tomodensitométrie dans le dépistage des cholestéatomes résiduels après chirurgie primaire.

Several recent studies have described the magnetic resonance imagery (MRI) of cholesteatomas. For certain authors the MR images are specific after Gadolinium injection. This radio-surgical study included 16 patients who underwent a tympanoplasty with supra and retromeatic masto-attictomy for a cholesteatoma and for whom a second operation was planned. Computed tomography (CT) and MRI was performed before operation in all patients with and without injection of Gadolinium. Images were then correlated with peroperative observations. Based on the CT and MRI diagnostic criteria of cholesteatoma reported in the literature, the radio-surgical correlation was false in 8 out of 16 cases (false negatives, false positives, partial errors). Among the 8 true correlations, 5 were normal images confirmed by the absence of cholesteatomy on operation. MRI with and without Gadolinium cannot be used to screen for small residual cholesteatomas or to determine the characteristics of an opacity of the middle ear seen on computed tomography.

Legg-Perthes-Calvé disease: staging by MRI using gadolinium.

Twenty-one patients (26 hips) with typical signs of Legg-Perthes-Calvé (LPC) disease on plain radiographs were explored by MRI. Patients were imaged with a 0.5 T MR unit. Gadolinium-enhanced spin-echo MR images were obtained after nonenhanced T1-weighted (spin-echo) and T2*-weighted (gradient-echo) images. Four different areas were identified in the femoral epiphysis (necrosis, regenerative, cartilaginous and normal fatty bone tissue). The histological evolution of LPC is well described by Catterall and others. Comparing their descriptions with our MR findings, we suggest classification of LPC into five phases: necrosis: regeneration, reconstruction, reossification and sequelae.

[Hypertrophic osteoarthropathy and congenital cyanotic heart defects]. / Ostéoarthropathie hypertrophiante et cardiopathies congénitales cyanogènes.

The association of hypertrophic osteoarthropathy and chronic pulmonary disease is well known. The authors report two cases of hypertrophic osteoarthropathy and tetralogy of Fallot in childhood. Early surgical treatment of the tetralogy of Fallot accounts for the present scarceness of this association. The clinical and radiological features of hypertrophic osteoarthropathy are described, as well as the regressive evolution after the cure of the cyanotic heart disease.

[Calcification of the umbilical artery in small infants]. / Calcifications de l'artère ombilicale chez le petit nourrisson.

The practice of systematic X ray screening for congenital dislocation of the hip leads to the discovery of a somewhat rare anomaly: the calcification of the vestigial segment of the umbilical artery. The authors describe 6 cases of this peculiar condition of which the diagnosis is easy and does not necessitate any complementary investigation. This finding has no pathological significance; this condition must be considered as a normal variant.

Beckwith-wiedemann syndrome and neural crest tumors. A report of two cases.

We report 2 cases of thoracic neural crest tumors complicating the course in patients with Beckwith-Wiedemann syndrome (BWS). In the first patient, a thoracic neuroblastoma was fortuitously discovered at age 3 months on a chest film prior to a partial glossectomy. In the follow-up left nephroblastoma and a right kidney simple cyst appeared. In the second patient, a thoracic tumor which proved to be a mature ganglioneuroma was discovered at age 4 years on a follow up spinal radiograph. Although less frequent than nephroblastoma and/or adrenal tumors, the occurrence of thoracic neuroblastoma in BWS suggests that periodic chest radiograph and assays of HVA, VMA and Dopamine should be included in the follow-up protocol.