Perfusion imaging in brain disease.

Perfusion CT or MRI have been extensively developed over the last years and are accessible on most imaging machines. Perfusion CT has taken a major place in the assessment of a stroke. Its role has to be specified for the diagnosis and treatment of the vasospasm, complicating a subarachnoid hemorrhage. Perfusion MRI should be included in the assessment of any brain tumor, both at the time of the diagnosis as well as in the post-treatment monitoring. It is included in the multimodal approach required for the optimum treatment of this disease. The applications in epilepsy and the neurodegenerative diseases are in the evaluation process.

[Dural carotid-cavernous fistulas: progression in therapeutic management from 1989 to 2004. A report of ten cases]. / Fistules carotido-caverneuses indirectes (durales): évolution de la prise en charge thérapeutique de 1989 à 2004. A propos de 10 cas.

INTRODUCTION: Dural carotid-cavernous fistulas are rare and require multidisciplinary management. Today there is no consensus on treatment, even though embolization is currently the first-line treatment. We present the cases of ten patients with a dural carotid-cavernous fistula diagnosed between 1989 and 2004 in order to compare the therapeutic choices used to treat dural carotid-cavernous fistulas in the late 1980s and mid-1990s to the therapeutic strategy currently favored. PATIENTS AND METHODS: The ten patients, with a mean age of 65.9 years, were seven women and three men. They had an ophthalmologic examination and the diagnosis was angiographically confirmed. Treatments were either noninvasive (such as decoagulation and/or carotid-jugular or ocular compression) or embolization. A combination of these different treatment modalities was provided for several patients. RESULTS: The main symptoms were arterialized conjunctival veins, proptosis, diminished visual acuity, chemosis, elevated intraocular pressure, and diplopia. Of the seven patients who only had noninvasive treatment (embolization not possible), three remained stable, three showed partial improvement, and the last one was clinically cured. As for the three patients treated with embolization (prior or not), this treatment led to a dramatic clinical improvement for one patient, a clinical cure for the second, and a complete cure in the remaining patient. CONCLUSION: Prior embolization when possible appears to be an effective and safe treatment for dural carotid-cavernous fistulas. Nonetheless, noninvasive treatment options, particularly compressions, remain an important therapeutic alternative.

How helical CT helps the surgeon in oculo-orbital trauma.

Whether isolated or associated with craniofacial lesions, traumatic oculo-orbital injuries occur frequently. Radiological evaluation is often necessary to appropriately manage the trauma-related vision loss and oculomotor disturbance. In the emergency setting and after clinical examination, helical CT scanning is the optimal imaging technique for displaying injuries of the orbit and its contents, for determining their severity and for helping the surgeon to choose the best course of treatment. MRI is indicated if the cause of the loss of vision or ocular mobility remain unexplained on CT after ferromagnetic foreign body has been ruled out. Drawing from numerous clinical cases, the purpose of this pictorial review is to demonstrate the wide variety of traumatic lesions of the orbit and eyeball as revealed by helical CT, as well as the limitations of the technique, to provide relevant information for patient care. Helical CT scans remain, in cases of emergency, the optimal imaging technique for the evaluation of oculo-orbital trauma.

[Schwannomas of the neck. About 3 cases, and literature review]. / Schwannomes du cou. A propos de 3 cas, revue de la littérature.

INTRODUCTION: Schwannomas of the neck are rare. Their diagnosis remains difficult despite the evolution of imaging techniques. The goals of our study were to review the diagnostic and therapeutic approach for these tumors. MATERIALS AND METHODS: Retrospective study (1998-2005) concerning 3 cases of schwannoma in rare localizations: superior laryngeal nerve, ansa cervicalis and deep cervical plexus. These 3 patients were operated on in our ENT head and neck department. We made a review of the literature using the Medline database. RESULTS: The mean delay between symptomatology and treatment was 5 years. In all cases, the schwannoma presented with a slowly-growing cervical mass. In only one case, the diagnosis of schwannoma was maded preoperatively. All 3 patients were treated surgically and the involved nerve was sacrificied. There were no postoperative complications. The mean follow-up duration was 3.5 years, with no recurrence. DISCUSSION-CONCLUSION: To establish a diagnosis of neck schwannoma, ultrasound is the least sensitive imaging tool. Fine needle aspiration is especially useful to rule out other conditions. The most relevant diagnostic tools are CT-scan and especially MRI. Treatment is surgical; it should include sacrifice of the involved nerve. Surgical exploration of the neck and tumor resection could be performed at the same operation in the informed patient aware of the sequelae of nerve sacrifice, or otherwise be performed in two steps in the uninformed patient.

CT Features of an unusual calcified schwannoma of the superior laryngeal nerve.

We report the CT findings in a patient with a lateral neck mass histologically diagnosed as a laryngeal schwannoma but presenting some uncommon CT features. CT showed unusual calcified components, very rarely observed and potentially misleading for diagnosis. However, this imaging feature can be found in ancient schwannomas. Our case is, therefore, a very rare one and reviews the main differential diagnoses.

[MR and CT perfusion imaging of the brain: principles and clinical applications]. / Imagerie de perfusion: principes et applications cliniques.

MR and CT imaging techniques provide both morphological data and functional data. MR and recently CT perfusion have substantially modified the treatment of acute stroke. CT perfusion offers new opportunities to improve the management strategy in vasospasm after subarachnoid hemorrhage. Both are also helpful for the diagnosis of brain tumors and the assessment of treatment effects.

[Perfusion-diffusion 1H spectroscopy: role in the diagnosis and follow-up of supratentorial brain tumours in adults]. / Spectroscopie 1H, perfusion, diffusion: quelle place pour ces techniques lors du diagnostic et du suivi des principales tumeurs cérébrales sus-tentorielles de l'adulte?

INTRODUCTION: In a few years, magnetic resonance imaging (MRI) has evolved from a morphology-based examination to one that encompasses metabolism and function. STATE OF ART: MRI is a well-established tool for the initial evaluation of brain tumors, but conventional MR sequences have some limitations. Conventional MRI is unable to distinguish high-grade glioma from metastasis and abscess, to define precisely the histopathological grade of gliomas, to determine exactly the limits of tumor extension, to characterize meningeal tumors. Differentiation of tumor recurrence from treatment-related changes may be difficult with standard MR imaging because the interpretation is essentially based on volume analysis. PERSPECTIVES: 1H Spectroscopy, diffusion and perfusion imaging become possible with the development of MR imagers and can be routinely performed in clinical settings. They give complementary information about tumor metabolism and vascularity and allow a better analysis of post-treatment modifications. Functional and metabolic explorations should be used to characterize brain tumors.

[Perfusion MR imaging in brain tumors]. / IRM de perfusion des tumeurs cérébrales.

Perfusion MR Imaging is useful for initial diagnosis and follow up of brain tumors. Dynamic susceptibility contrast MR imaging is described. The limitations and advantages of this technique are discussed with respect to quantification and interpretation of results.

[Brain perfusion and metabolism imaging techniques]. / Imagerie de la perfusion et du métabolisme cérébral.

Due to recent efforts in improving spatial and temporal resolution in imaging techniques, it is now possible to get relevant information about brain perfusion and metabolism in humans. This information can significantly impact on brain pathophysiology, diagnosis assessment and therapy options, particularly in patients having brain ischemia. Among these imaging and metabolism techniques are dynamic perfusion computed tomography, perfusion MRI, positron emission tomography and NMR spectroscopic imaging. The goal of this article is an overview of these four techniques, with their own technical description, advantages and drawbacks. Details are provided about brain parameters given by each technique and their clinical relevance, the accessibility of the technique in the emergency setting and the optimal window to use it during the patient's evolution.

[Magnetic resonance cerebral blood volume maps. Comparison with histologic findings in different types of brain lesions]. / Volume sanguin cérébral déterminé par IRM de perfusion.

Recent developments in magnetic resonance (MR) have made it possible to obtain measurements of the microvasculature within brain lesions. Cerebral blood volume (CBV) maps calculated from dynamic contrast-enhanced MR imaging are particularly sensitive for depicting the microvasculature, and can enable the detection of neovascularization as well as its quantification in relative terms. The purpose of the present work is to compare the results of CBV maps calculated from MR imaging with those from histologic examination of the same region of interest: the biopsy site. Nineteen patients with brain lesions were studied (18 brain tumors and one case of multiple sclerosis). All patients underwent stereotactic biopsy, and calculation of CBV was performed from perfusion MR imaging. Three histopathologic parameters were assessed: the number of vessels (vessel density), the vessel size and the surface area filled by vessels (%). We observed a statistically significant correlation between the vessel density and the CBV, which is consistent with some previous publications. A noninvasive imaging method for characterizing the functional properties, especially hemodynamic activity, of malignant processes seems to be of great benefit to clinical practice.

Cerebral blood volume mapping by MR imaging in the initial evaluation of brain tumors.

PURPOSE: To assess the contribution of magnetic resonance (MR) cerebral blood volume (CBV) mapping in the initial evaluation of brain tumors. METHODS: 63 patients presenting a brain tumor underwent dynamic susceptibility-contrast MR imaging before surgery or biopsy: 28 high grade gliomas, 8 low grade gliomas, 2 pilocytic astrocytomas, 4 lymphomas, 12 metastases, 9 meningiomas. The CBV maps were obtained for each patient and the relative CBV (rCBV) in different areas was calculated using the ratio between the CBV in the pathological area (CBVp) and in the contralateral normal tissue(CBVn). The maximum rCBV (rCBVmax) for each tumor was determined and the mean values of rCBVmax in each group of tumors were compared using an unpaired Student t test (p=0.05). RESULTS: The rCBVmax for high grade gliomas (mean +/- SD: 2.6 +/- 1,2) was statistically different from low grade gliomas (0.9 +/- 0.4) (p<0.001), lymphomas (0.7 +/- 0.2) (p=0.002), meningiomas (9.1 +/- 4.4) (p<0.001) and kidney metastases (8.9 +/- 2.1) (p<0.001). The two pilocytic astrocytomas had a much lower rCBVmax than high grade gliomas. No statistically significant difference was found between high grade gliomas and lung metastases (2.4 +/- 0.9) (p=0.72). CONCLUSION: CBV mapping provides additional information on the vascularity of the lesions, which is not available with conventional MR imaging. It might be useful for differentiating certain lesions showing contrast enhancement, mainly high grade gliomas from kidney metastases, meningiomas, lymphomas or pilocytic astrocytomas.

A persistent pharyngohyostapedial artery: embryologic implications.

A 3-year-old child was examined because of otorrhagia. CT scans showed an unusual vessel, confirmed by angiography, related to a persistent pharyngohyostapedial artery. This embryonic persistent artery associated with the normal internal carotid artery would explain the "duplication" aspect of the internal carotid artery.

[Benign vertebral osteoblastoma. Report of 6 cases]. / L'ostéoblastome bénin vertébral. A propos de 6 observations.

We present six cases of benign spinal osteoblastoma. This localization of this uncommon benign bone tumor occurring in young subjects is rare. The patients were explored with radiotomography, computed tomography, myelography and medullo-spinal angiography. These benign tumors may appear radiographically as pure bone lysis mimicking malignancy. The size of these tumors often leads to widening search for extension, particularly in recurrent, aggressive, multifocal forms which require wide resection, and sometimes total vertebrectomy. Medullo-spinal angiography can confirm the vascular involvement of the tumor nidus and is require to identify arteries supplying the spinal canal which would modify operative strategy.

Direct emergence of the dorsospinal artery from the aorta supplying the anterior spinal artery: report of two cases.

We report two cases of an isolated dorsospinal artery that emerged directly from the aorta to supply the anterior spinal artery, which in one case had another blood supply on the opposite side, in a lower position. It is important to identify this anatomic variant, otherwise spinal angiography might be incomplete, especially when the isolated dorsospinal artery supplies the anterior spinal artery.

[Intracranial dural fistula with spinal cord venous drainage. Apropos of 2 cases]. / Les fistules durales intracrâniennes a drainage veineux périmédullaire. A propos de deux observations.

The authors report 2 new cases of intracranial dural fistula draining into spinal veins. Comparisons with 19 other published cases showed that dural fistulae of the spine share common features with intracranial fistulae. The first case concerned a 78-year old woman presenting with a thoraco-lumbar myelopathy which proceeded by increasingly severe bouts and ended within 6 months in a flaccid sensorimotor paraplegia with urinary incontinence. Paraclinical examinations consisted of MRI, myelography and spinal as well as cerebral arteriography. MRI and thoraco-lumbar myelography displayed marks of dilated retrospinal vessels. Spinal arteriography showed no arteriovenous malformation, but the venous return of Adamkiewicz artery was not visible. Diagnosis was made by cerebral arteriography which demonstrated an intracranial arteriovenous fistula in the occipital region, draining into the posterior spinal vein. Treatment was endovascular and consisted of embolization by micro-coils, but clinical improvement was mediocre. Six months later, as the clinical picture was getting worse a second arteriography was performed. It showed recanalization of the fistula which was embolized again, using both coils and particles. No improvement in spinal cord deficit was observed. The second case was that of a 42-year old man presenting with paraparesis, tetrapyramidal syndrome, sensory deficit at T9, peribuccal dysaesthesias and genito-urinary sphincteral disorders, all gradually getting worse. The paraclinical exploration was the same as in the first case. MRI and myelography showed retrospinal vascular impressions. Spinal arteriography was normal, except for the lack of venous return of Adamkiewicz artery. Cerebral arteriography detected an intracranial dural arteriovenous fistula in the occipital region, draining into the anterior and posterior spinal veins. Treatment was surgical, consisting of exclusion of the arteriovenous fistula. Partial clinical improvement was noted. These two cases, compared with those of the literature, shared a number of features with spinal dural arteriovenous fistulae: they occur in middle-aged and predominantly male patients, and the clinical signs of ascending myelopathy are caused by the same physiopathological mechanism of spinal vein hyperpressure. Lesions of the medulla oblongata or the cervical spinal cord are found only in intracranial arteriovenous fistulae draining into spinal veins. Diagnosis is based on data provided by myelography (impressions of dilated and sinous vessels) and MRI (low-intensity perispinal signals, widening of the conus medullaris with high-intensity centrospinal signal); spinal cord angiography only shows a lack of venous return of Adamkiewicz artery without any other abnormality, whereas cerebral arteriography confirmed the diagnosis of intracranial dural arteriovenous fistula draining into spinal veins.

[Computed tomographic aspects of secondary cholesteatomas of the middle ear and petrous bone]. / Aspects tomodensitométriques des cholestéatomes secondaires de l'oreille moyenne et du rocher.

The authors present their experience of secondary cholesteatomas of the middle ear explored by computerized tomography (CT). Following a brief anatomicopathological description of secondary petrous bone cholesteatomas, and of the CT technique used for their exploration, they describe and illustrate the classical "bag-shaped" internal or external attical forms usually extended to the antrum and the mastoid process, and the less common locations often due to relapse or postoperative recurrences (anterior hypotympanic or posterior mastoidal). The holotympanic forms, usually due to "lamellar" cholesteatomas, create diagnostic problems with other opacities in the cavity, as also do certain forms that are evacuated spontaneously or by aspiration. One of the qualities of CT lies in the preoperative extension assessment. The lesion may extend towards the internal wall of the cavity (lateral semicircular canal, second portion of the facial nerve), towards the labyrinth to the petrosal apex and/or the geniculate ganglion, and above all towards the inferior labyrinth which might bring the cholesteatoma into contact with large vessels (e.g. jugular vein bulb for postero-inferior extensions, carotid canal for antero-inferior extensions). Extension into anfractuosities of the cavity walls (sinus tympani, subratubal fossette) must be systematically looked for in order to avoid postoperative recurrences.