[Neuroimaging: technical aspects and practice]. / Neuroimagen: Fundamentos técnicos y prácticos.

Neuroimaging using both functional and structural examinations like positron emission tomography (PET), single photon emission tomography (SPECT), computed tomography (CT) and magnetic nuclear imaging (MRI) provide supportive information of great importance for the diagnosis and treatment of patients with central nervous system disorders. Therefore, they have become commonplace in clinical practice and basic biomedical research. In recent years we have seen the development of multimodality equipment that enables PET or SPECT to be combined with a CT structural image. Moreover, experimental equipment combining PET and MRI has now been developed. Additionally, methodological features that provide a higher image quality, and analysis tools for objective quantification and interpretation have been refined. This article reviews the technical aspects of those imaging methods, highlighting the most significant and recent advances in the development of neuroimaging.

[Neuro-otological manifestations as presentacion of type I Chiari malformation]. / Manifestaciones otoneurológicas como presentación de la malformación de Chiari tipo I.

The type I Chiari malformation consists of an caudal descent of the cerebellar tonsils through the foramen magno towards the spinal cervical channel. The usual clinical presentation are occipital headaches and cervical pain, as well as some otoneurological symptoms. Among them are common dizziness and crisis of central positional vertigo in which down beating nystagmus can be observed. We present our experience with three cases presenting with neurotological manifestations in which MRI showed a type I Chiari malformation. Case 1: a patient of 24 years that had frequent instability, and common crisis ofpositional vertigo. It was possible to see the presence of positional down-beating nystagmus, of central characteristics, that improved after neurosurgical treatment. Case 2: patient of 11 years who suffered from occasional headaches, dizziness and positional vertigo, without severe handicap, and did not need surgery. Case 3: lady of 63 years who had common episodes of vertigo with head tilt, and unsteadiness during walks. Due to the coexistence of hydrocephalus and syringomyelia, surgery was indicated. A revision is done on otoneurological presentation of type I Chiari malformation, especially as differential diagnosis on central positional vertigo.

[The use of magnetic resonance in the study of sensorineural hearing loss in children]. / Utilidad de la rm en el estudio de la hipoacusia neurosensorial unilateral infantil.

Although newborn screening of congenital hearing loss through otoacustic emissions allow prompt recognition, imaging techniques, such as CT and MRI are needed to get a morphological diagnosis. Furthermore they can be very useful in unilateral cases, whose clinical presentation is belated and more insidious. Our aim is to show the utility of MRI in the study of inner ear congenital anomalies, whose presentation is belated. Thus from a series of 88 consecutive patients in which a MRI was performed as screening of assymetric sensorineural hearing loss, we selected 6 cases aged between 6 and 20. Four of them showed an inner ear anomaly on MRI. We present these anomalies commenting the findings on CT and MRI. Imaging techniques are required to start hearing rehabilitation programs early on patients with bilateral inner ear anomalies. But also they are very useful in the evaluation of unilateral assymetric sensorineural hearing loss, in young patients, even if only some frequencies are damned, to determine the nature of hearing loss.

[What clinical significance do vascular anomalies of the outer ear canal have?]. / Cuál es el significado clínico de las anomalías vasculares del conducto auditivo interno?

Vascular anomalies of the internal auditory canal (IAC) are relatively common, being found in 20-25% of magnetic resonance imaging (MRI) studies performed in patients with unilateral sensorineural hearing loss. They are usually asymptomatic and their diagnosis is almost always based on MRI, as they are generally undetected by routine clinical examination. Recently, the clinical relevance of these IAC anomalies and the effectiveness of vascular decompression have been debated. We present a series of 7 vascular anomalies of the IAC found in a series of 83 consecutive MRI scans performed in a screening program for IAC and cerebellopontine angle pathology. We reviewed their clinical and radiological presentation to evaluate their clinical relevance. In this series, we found no correlation between the presence of such vascular anomalies and the clinical symptoms that motivated MRI, so we conclude that most of these anomalies were accidental findings.

[Magnetic resonance: first choice test in the screening of internal auditory canal and cerebellopontine angle tumors]. / Resonancia magnética: prueba de elección en el despistaje de tumores del conducto auditivo interno y ángulo pontocerebeloso.

Although internal auditory canal (IAC) and cerebellopontine angle (CPA) tumors are rare, their clinical suspicion is quite common in the otolaryngology office. MRI is the imaging modality of choice in diagnosing these tumors. Perceived high costs may prevent clinicians from using it as a screening tool. A protocol designed to improve cost-effectiveness in such diagnosis results in a more rationale clinical practice. Our aim was to evaluate the usefulness of MRI as screening tool in diagnosis of IAC and CPA tumors in our population. Between March 1998 and March 2000, a prospective series of 200 cases had a MRI screening requested. MRI were performed following Fast Spin Echo technique, providing T2-weighted images. Gadolinium enhanced MRI was reserved for selected cases. We report on 190 MRI done. We found 7 neuromas (3.5%), one CPA metastasis, one epidermoid cyst and 9 IAC vascular anomalies. Only 138 cases (69%) had normal MRI images. When used following a designed protocol, MRI is our procedure of choice while screening IAC and CPA tumors because it is a cost-effective tool.

[Carotid-cavernous fistulas. A report of two cases]. / Fístulas carótido-cavernosas. A propósito de dos casos.

Carotid-cavernous fistulas are uncommon anomalous communications between the venous cavernous sinus and the carotid arterial system. We present two cases studied at our center. We show the characteristic CT, MRI, and orbital ultrasound findings and review the relevant literature.

Vertigo and Parinaud's syndrome as presentation of Churg-Strauss syndrome.

Intracranial complications are rare in Churg-Strauss syndrome (CSS). Cerebral infarctions are the most common intracranial presentation, usually after the clinical diagnosis of CSS had been established. We present a case of vertigo and Parinaud's syndrome as presentation of CSS in an asthmatic patient. Clinical examination revealed upward gaze limitation and bilateral midriasis. A cranial computed tomography scan showed a small round hypoattenuating lesion located in the right thalamic-mesencephalic region, which was later confirmed by magnetic resonance imaging. There was eosinophilia of more than 50%, and p-ANCA were positive. After steroid treatment was started, vertigo and diplopia resolved, and eosinophilia was reduced. After 24 months follow-up, the patient remains stable, with negative p-ANCA, taking 20 mg prednisone daily. Further magnetic resonance exams have shown findings that were similar to those of previous studies. This case shows how vertigo and transient diplopia may be the first symptoms of neurological complications in patients with CSS.

[Precocious puberty and pituitary incidentaloma]. / Pubertad precoz e incidentaloma hipofisario.

The case of an 9-year-old girl with precocious puberty and a non-functioning pituitary adenoma is described. A review of the literature on the incidence, evolution and therapeutic options of pituitary incidentalomas in children and adults is performed.