Three-dimensional reconstruction of the temporal bone: Comparison of in situ, CT, and CBCT measurements.

OBJECTIVE: To evaluate the accuracy of three-dimensional (3D) Cone Beam Computed Tomography (CBCT) and Computed Tomography (CT) reconstructions of human temporal bones compared with in situ measurements. MATERIAL AND METHODS: Experimental anatomical study of 10 human temporal bones. Wilcoxon's test was used to compare 8 distances on each temporal bone measured in situ and then on 3D CT and CBCT reconstructions. Six landmarks were used: external auditory canal (EAC), tip of the mastoid process, tip of the occiput, zygoma, a point situated 1cm above the tip of the mastoid process (T0) (open technique: lower limit of the mastoidectomy), head of stapes. RESULTS: No significant difference was observed between the 3 measuring techniques for any of the distances studied (P>0.05). DISCUSSION: This study demonstrates the equivalence of CBCT and CT for temporal bone measurements. CONCLUSION: CBCT is a new imaging modality providing 3D reconstructions of the temporal bone that are as reliable as those obtained by CT. As a result of better spatial resolution compared to CT, CBCT is associated with a significantly lower radiation dose. This technique constitutes a morphological progress, as CBCT is comparable to CT, allowing investigation of pathological ears with a lower radiation dose.

Diagnostic accuracy of diffusion-weighted MR imaging versus delayed gadolinium enhanced T1-weighted imaging in middle ear recurrent cholesteatoma: A retrospective study of 39 patients.

OBJECTIVE: MR imaging using diffusion-weighted (DW) images and delayed gadolinium-enhanced T1-weighted images is evolving into an alternative to second look surgery in detection of recurrent cholesteatomas. The aim of this study was to retrospectively compare the DW images, the post-gadolinium T1-weighted images and the combination of both methods in this indication. PATIENTS AND METHODS: We retrospectively evaluated the MR examination of 39 patients clinically suspected for a recurrent cholesteatoma. Patients in the study underwent DW sequences, delayed gadolinium enhanced T1-weighted sequences as well as standard uninjected protocol using T1 and T2 sequences. Three blinded radiologists evaluated three data sets: a set of post-gadolinium T1-weighted images, a set of DW images and a set of the combination of both methods. The interobserver agreement was evaluated and the diagnostic accuracy of each method was described by sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The performances of the three techniques were also evaluated using ROC curves, from which the AUC were compared. Results were compared with surgical results or a two-year follow-up. RESULTS: The overall sensitivity and specificity were respectively 63% and 71% for the post-gadolinium T1-weighted images, 88% and 75% for the DW images and 84% and 75% for the combined images. The PPV and NPV were respectively 89% and 33% for the post-gadolinium T1-weighted images, 93% and 62% for the DW images and 93% and 55% for the combined images. The sensitivity and the NPV were significantly different between the three methods (P<0.0001 and P=0.027). There was no statistically significant difference in specificity or PPV between the three methods (P=0.931 and P=0.650). The diagnostic accuracy evaluated with the AUC showed no statistically significant difference between the DW images and the combined images (P=0.433). CONCLUSION: MR imaging reliably identifies those patients suspected for recurrent cholesteatoma who require a surgical second look by using DW MR imaging. The combination with delayed gadolinium enhanced T1-weighted sequences does not significantly increase the diagnostic accuracy of the examination.

Biometry of the normal stapes using stapes axial plane, high-resolution computed tomography.

OBJECTIVE: The stapes is difficult to analyse on computed tomography because of the small size of its components and its oblique orientation. The stapes axial plane, parallel to the superstructure, seems optimal for this purpose. The present study assessed the position of the stapes axial plane with respect to the usual axial plane including the lateral semicircular canal, and sought to measure the main dimensions of the stapes. METHODS: This retrospective study comprised 208 computed tomography scans of normal ears. Stapes length and width, footplate thickness and incudostapedial joint width were measured. RESULTS: The stapes axial plane was directed upward, outward (44°) and forward (12°) with respect to the lateral semicircular canal plane. Mean head-to-footplate distance was 3.7 mm and mean superstructure width was 2.7 mm. Mean footplate thickness was 0.27 mm on stapes axial plane versus 0.48 mm on lateral semicircular canal plane. Incudostapedial joint width was systematically less than 0.7 mm. CONCLUSION: Stapes dimensions on stapes axial plane were close to anatomical data, particularly for footplate thickness.

[Brachioradial pruritus revealing an ependymoma]. / Prurit brachioradial révélant un épendymome.

BACKGROUND: Brachioradial pruritus is a rare form of pruritus localised to one or more brachioradial dermatomes, initially classified as a photodermatosis but which in fact is generally brought on by nervous compression. We report a case of a brachioradial pruritus revealing an intramedullary tumour. PATIENTS AND METHODS: A 53-year-old man had presented pruritus for seven years under the left clavicle, then on the left forearm followed by the right forearm. Finally cervicodynia appeared associated with dysaesthesia of the two upper limbs, fulgurating pains and paresis of the left cubital region. The examination revealed suspended bilateral hypoaesthesia (C4, C5, C6, C7), proprioceptive disorders of the left upper limb, mild motor deficit in the left C8 area and tetrapyramidal syndrome. Cervical radiography did not show cervical osteoarthritis. The MRI revealed a bulky cervical intramedullary tumour extending from C2 to C6. After ruling out cavernoma by medullary angiography, surgery was performed and histopathological analysis of the complete lesion revealed a benign ependymoma. Four months later, this patient complained about residual pains requiring treatment with gabapentin and class 2 analgesics. DISCUSSION: The case presented underlines the possibility of a brachioradial pruritus revealing an intramedullary tumour. Ependymomas are usually seen in children and are frequently evoked in the presence of dysaesthesia. We report the third case of brachioradial pruritus revealing a medullary tumour. The two other cases involved syringomyelia revealed by pruritus in C5 and ependymoma revealed by pruritus in C5-C6. The patient with ependymoma had refused surgical treatment. CONCLUSION: Atypical brachioradial pruritus complicated by neuropathic pains and disorders should prompt screening for a medullary tumour.

[Post-traumatic orbital emphysema: a case report]. / Emphysème orbitaire post-traumatique: à propos d'un cas.

Orbital emphysema is often associated with orbital fracture or communication with paranasal sinuses. It is usually moderate but could be the cause of optic neuropathy or central retinal artery occlusion. We report a case of massive orbital emphysema with ocular hypertony and prethrombosis of the central retinal artery. Emergency surgical decompression performed by an ophthalmologist and an otorhinolaryngologist provided complete and prompt relief. The authors emphasize the importance of preventing nose blowing after orbital trauma or surgery.

Hypophysitis associated with a ruptured Rathke's cleft cyst in a woman, during pregnancy.

We report the case of a 29-yr-old woman who first presented an aseptic meningitis at the beginning of a pregnancy. She was admitted one month later with headaches and vomiting. Panhypopituitarism with diabetes insipidus was diagnosed. Magnetic resonance imaging (MRI) data suggested the existence of lymphocytic infundibulohypophysitis, with inflammation of the suprasellar area. No new symptoms were noticed until 6 months later when this patient pointed out troubles of the visual field, due to a compression of the optic chiasma. Three boluses of 1 g methylprednisolone were prescribed, with no effects. After delivery, the defects of the visual field increased. A neurosurgical intervention was decided. Diagnosis of Rathke's cleft cyst (RCC) was made. We concluded that this patient presented a rupture of a RCC, which occurred at the beginning of pregnancy, associated later with panhypopituitarism with diabetes insipidus, due to a probable hypophysitis. The end of the pregnancy was marked by consequences of an increased volume of the RCC. To our knowledge, this case is the first described during pregnancy.

[Persistence of the stapedial artery: three cases]. / Persistance de l'artère stapédienne: à propos de trois observations.

The authors report three cases of persistence of the stapedial artery, discovered by computed tomography examination. For two cases, a clinical symptomatology was present but probably related to the association with an aberrant carotid artery in the middle ear; the only case of isolated persistence of the stapedial artery was asymptomatic. Direct visualisation of the abnormal artery was possible on the C. T. scans in two cases and a collateral sign as a larger tympanic part of the facial canal was found in the third case inducing a MRI. The incidence of this anomaly is 0.48 per cent from 1,045 dissections of temporal bones but it is generally clinically unrecognized. The hyoïdo-stapedial artery appears and develops at the 7-18 mm embryonic stages. Partial or complete persistence have been described associated with no regression or no division of the ventral pharyngeal artery.

[Imaging of post-traumatic tinnitus, vertigo and deafness]. / Imagerie des acouphènes, vertiges et surdité post-traumatiques.

Tinnitus, hearing loss, and more rarely disequilibrium are common sequela of temporal bone trauma. Hemotympanum may cause a transient and immediate conductive hearing loss. HRCT depicts ossicular dislocation (most frequently incus), producing a long-term conductive hearing loss. Labyrinthine trauma causing neurosensory hearing loss or/and acute vertigo may be depicted by MRI, showing an abnormal non-enhancing high signal T1 of the membranous labyrinthine fluid. MRI also may show low signal T1 and T2 fibrotic areas of the membranous labyrinth, especially of interest if cochlear implant surgery is planned. Perilymphatic fistulas are to be searched in case of fluctuant hearing loss. Both HRCT and MRI may show window damage: filling of the tympanic recess, rupture of the window membrane, intra-vestibular luxation of the stapes, or occasionally pneumolabyrinth.

CT appearances of ossicular injuries.

Trauma of the ossicular chain is a frequent complication of temporal bone injury. Skull trauma from blows to the temporal, parietal, or occipital region (with or without fracture of the temporal bone) is the main cause of ossicular injury; other modes of injury are rare. Ossicular injury usually occurs as a dislocation, of which there are five types: incudostapedial joint separation, incudomalleolar joint separation, dislocation of the incus, dislocation of the malleoincudal complex, and stapediovestibular dislocation. Fracture of the malleus, incus, or stapes is uncommon. High-resolution computed tomography is the method of choice for evaluation of ossicular trauma. Joint separation and fracture of the stapes are seen on axial images; coronal images may aid visualization. Both axial and coronal images are needed for evaluation of a dislocated malleus or incus. Fracture of the malleus or incus is detected with axial or coronal images; reformatted images may also be useful.

[Benign glial cysts of the pineal region]. / Les kystes gliaux bénins de la région pinéale.

A review of the pertinent literature regarding glial cysts of the pineal region is presented. Various pathogenic factors have been advocated such as the physiological involution of the pineal gland, a sequestration of the embryonic cavum pineale or the degenerative evolution of glial inclusions within the pineal gland. The pathological description is classical with three layers: an external fibrous capsule, an intermediate layer of pineal tissue and an internal glial wall. Imaging of these lesions is typical, namely the thin rim of peripheral contrast enhancement and the presence of calcifications. These cysts are more frequent in women in their third decade of life. They are almost always latent and their fortuitous disclosure at NMR examinations is common. Some of them will nevertheless cause intracranial hypertension due to hydrocephalus and hemorrhage. Those symptomatic cysts should be treated. Surgical excision has been the method of choice and the results are good. More recently a mere stereotactic needle aspiration has been performed with satisfactory long-term results.

[Benign hemorrhagic cyst of the pineal region. Treatment by stereotactic puncture. 4-year follow-up]. / Kyste bénin hémorragique de la région pinéale. Traitement par ponction stéréotaxique. Recul de quatre ans.

We report the case of a 27 year-old male patient in whom acute intracranial hypertension led to the diagnosis of a pineal hemorrhagic cyst as demonstrated by CT-scan and MRI examinations. Treatment consisted in stereotactic needle-aspiration following insertion of a ventriculo-peritoneal shunt. Pathological examination confirmed a benign glial lesion. The outcome was good as complete shrinkage of the cyst and complete relief of the signs and symptoms were achieved. These clinical and radiological results persisted over four years. Approximately 70 cases of symptomatic benign pineal cysts have been reported to-date. Surgical excision has been the method of choice. The present case and twelve other cases of stereotactic management of the condition in the literature suggest the interest of a mere stereotactic needle aspiration of these lesions.

[Endovascular treatment of traumatic and iatrogenic intrarenal arterial lesions by microcoil embolization]. / Traitement endovasculaire par microspires des lésions artérielles intrarénales traumatiques et iatrogènes.

Selective embolization is the best treatment for intrarenal arterial lesions due to trauma or percutaneous procedures with non-controlled or recurrent haematuria. Three male patients, aged 20-70 (mean 49 years), were recently treated in our institution by means of arterial embolization with microcoils. Two patients presented a pseudo-aneurysm and an arterio-venous fistula secondary to percutaneous nephrolithotomy and one patient presented an isolated pseudo-aneurysm due to trauma. In the 3 cases, haematuria (associated with retroperitoneal haemhorrage in one case) was not controlled and required repeated units of blood. Embolization allowed definitive treatment of these lesions. One of our patients with a solitary functional kidney presented rapidly increasing renal failure which completely resolved after arterial embolization. We think that microcoils are the embolic agents of choice to perform endovascular treatment in this indication.

[Congenital neck masses. Embryonic origin and diagnosis. Report of the CIREOL]. / Pathologie cervicale congénitale. Origine embryologique et diagnostic. Rapport du CIREOL.

Various congenital cervical anomalies are found in the neck region including defects of the branchial apparatus (branchial, thymic and parathyroid anomalies) and vascular anomalies. They manifest as cystic masses, sinuses, fistulas and as ectopic glands. This multicentric retrospective imaging study done in 5 different radiological centers (4 adult radiological departments and 1 pediatric radiological department) shows the result in understanding the congenital cervical anomalies and include 63 patients. The age of the patients varied between 24 days-81 years with a mean age of 23 years. This study included 27 patients having congenital branchial pouch anomalies (4 cases of anomalies of obliteration of the 4 th arch), 14 cases of cervical cystic hygromas, 11 thyroglossal tract cyst cases, 1 congenital laryngocele case, 1 case of jugular ectasia, 3 cases of capillary haemangioma. The embryologic basis of these different malformations were reviewed. Their characteristic findings and sites were illustrated together with their typical et atypical appearances. The frequency of occurrence of each branchial anomaly were plotted, the second branchial cleft cyst being by far the most common congenital cystic neck mass (70%). The study revealed the role of different imaging modalities in the diagnosis of various congenital cervical anomalies, especially in some particular complicated cases of congenital neck masses presenting in adult. Imaging study helps the clinician to anticipate any difficulties in unforeseen circumstances that may arise including infection haemorrhage, or parapharyngeal extension. Understanding the various radiologic appearances of these anomalies is greatly aided by familiarity with their embryologic origin. Moreover, considering the anatomic location and radiologic appearance, the precise embryologic origin can be accurately predicted.

[Juxta- or trans-condylar lateral extension of the posterior suboccipital approach. Anatomical study, surgical aspects]. / L'extension latérale juxta- ou transcondylienne de la voie sous-occipitale postérieure. Etude anatomique, intérêt chirurgical.

In order to improve the surgical approach to tumors and aneurysms of the anterior or antero-lateral aspect of the foramen magnum, some authors have proposed a lateral extension of the posterior sub-occipital approach to the occipital condyle including in some cases its partial or complete resection. The evaluation of this close medio-condylar or trans-condylar suboccipital approach has been performed on eight coloured-latex injected specimens in the conditions of a microsurgical operation. The extra- and intradural steps have been studied so as to define the optimal position of the patient's head and the surgeon and to precise the accessible anatomical structures: Vertebral artery (and its control), Cranial nerves IX, X, XI & XII, Posterior-inferior cerebellar artery and collaterals, Vertebro-basilar junction, antero-lateral aspect of the brain stem and spinal cord. Depending on the extent of the condylar resection, the lateral extension of the posterior sub-occipital approach may be defined as minimal, moderate or large. Based on anatomical and surgical constations it appears that a complete resection of the occipital condyle (resulting in occipito-cervical instability) should be reserved for those very extensive lesions. Yet a partial drilling of the condyle provides a better angle of approach, minimises the hazards of retraction of nervous structures and enables the surgeon to take the best advantage of the dissection and control of the vertebral artery.

[3-dimensional reconstruction of x-ray computed tomographic views in fractures of the acetabulum]. / Reconstructions tridimensionnelles à partir de coupes tomodensitométriques dans les fractures du cotyle.

In 21 cases of acetabulum fractures of 19 patients, the authors compare the findings given by three dimensional reconstructions of axial CT scan cuts with the plain films. The number of CT scan cuts is reasonable for each patient. Working time is about 20 to 30 minutes for the technician. In the cases of complex and displaced fractures, three dimensional imaging brings often decisive informations for the therapeutic management of these patients. Unusual views are often allowed but completely adapted to each type of fracture.

[A simple method for measuring anteversion of the acetabulum from a frontal radiograph of the hip]. / Une méthode simple de la mesure de l'antéversion du cotyle á partir d'une radiographie de la hanche de face.

A simple, reproducible and reliable method is proposed for measurement of cotyloid version. Using a standing frontal image of hip, the cotyloid borders are identified and a single-plane geometric projection determines the precise degree of version. This study can also be made from a conventional frontal pelvic image with bipodalic weight bearing. Knowledge of spatial orientation allows a better approach to head-cotyle biomechanical phenomena and thus improved understanding of the genesis of certain hip diseases.

Radiologic anatomy of duplication of the inferior vena cava: a trap in abdominal imaging. A report of 8 cases.

Eight cases of duplication of the inferior vena cava are reported. Three of these bear witness to the errors of interpretation that may be committed when the anomaly is not initially detected in the ultrasonographic transverse sections and when no preliminary phlebography is available. Two other cases illustrate the influence of this duplication on the choice of the prophylactic surgical treatment of pulmonary embolism. The last clinical observation indicates the need to puncture both the femoral veins when performing iliocaval phlebography. Finally, two observations on the cadaver help to clarify the imaging appearances of this anomaly. The report concludes with a review of the classical anatomic and pathogenic concepts and a short discussion of the practical problems posed by duplication of the inferior vena cava.

[Transverse fracture of the 2nd sacral vertebra with neurological signs. Apropos of a case]. / La fracture transversale de la deuxième vertèbre sacrée avec signes neurologiques. A propos d'un cas.

The authors report a case of transverse fracture of the second part of the sacrum with neurological signs. Whilst such a lesion would appear very rare, associated involvement of the sacral roots is very common. Recovery of the neurological deficit syndrome is hazardous. A review of the literature fails to provide the basis for a defined programme of management.