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1.
J Inherit Metab Dis ; 30(2): 209-16, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17245558

RESUMEN

OBJECTIVE: To gain insights into the nature and pathogenesis of white matter (WM) abnormalities in PKU. METHODS: Thirty-two patients with phenylalanine hydroxylase deficiency (21 with early and 11 with late diagnosis and treatment) and 30 healthy controls underwent an integrated clinical, neuroimaging (3.0 T MRI, diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI)) and neurochemical (1H MRS) investigation. RESULTS: All patients had white matter abnormalities on T2-weighted (T2W) and fluid-attenuated inversion recovery (FLAIR) scans; parietal white was consistently affected, followed by occipital, frontal and temporal white matter. T1-weighted hypointense alterations were also found in 8 of 32 patients. DWI hyperintense areas overlapped with those detected on T2W/FLAIR. The apparent diffusion coefficient (ADC) was reduced and correlated inversely with severity of white matter involvement. Fractional anisotropy index, eigenvalues lambda(min), lambda(middle), lambda(max) obtained from DTI data, and the principal brain metabolites assessed by 1H MRS (except brain phenylalanine (Phe)) were normal. Brain Phe peak was detected in all but two subjects. Brain and blood Phe were strictly associated. Blood Phe at the diagnosis, patient's age, and concurrent brain Phe independently influence white matter alteration (as expressed by conventional MRI or ADC values). CONCLUSIONS: (a) MRI abnormalities in phenylketonuria are the result of a distinctive alteration of white matter suggesting the intracellular accumulation of a hydrophilic metabolite, which leaves unaffected white matter architecture and structure. (b) White matter abnormalities do not seem to reflect the mechanisms involved in the derangement of mental development in PKU. (c) Our data do not support the usefulness of conventional brain MRI examination in the clinical monitoring of phenylketonuria patients.


Asunto(s)
Encéfalo/patología , Imagen de Difusión por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Fenilcetonurias/diagnóstico , Adolescente , Adulto , Encéfalo/metabolismo , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fenilalanina/sangre , Fenilalanina/metabolismo , Fenilcetonurias/sangre , Fenilcetonurias/metabolismo , Índice de Severidad de la Enfermedad
2.
Eur J Neurol ; 13(12): 1364-9, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17116221

RESUMEN

Brain magnetic resonance imaging (MRI) studies in migraine patients have demonstrated lesions consisting of focal regions of increased signal intensity within the white matter. Antiphospholipid antibodies are known to have a role in many diseases including migraine. The aim of the present study was to ascertain the relationship between MRI-visualized cerebral focal hyperintense lesions and serum antiphospholipid antibody levels, as well as blood coagulation parameters in migraine patients. One hundred and two (77 females, 25 males, mean age 33.8 +/- 11.1) consecutive migraine patients and a control group of 94 (70 females, 24 males, mean age 33.2 +/- 10.8) healthy subjects were enrolled. All individuals underwent brain MRI. Complete blood examinations, autoantibodies, antiphospholipids antibodies including anticardiolipin and lupus anticoagulant (aCL, LAC), antithrombin III, Protein C and S serum levels were ascertained in the subjects who presented white matter lesions on MRI. Twenty-seven (26.4%) migraine patients and six (6.3%) healthy subjects in the control group showed focal regions of increased intensity signal within cerebral white matter (odds ratio 5.3, 95% CI: 1.98-16.36). In migraine patients with white matter lesions, antiphospholipid antibodies were not detected and serum levels of antithrombin III, and proteins C and S were normal. White matter lesions in migraine patients are fairly common. This finding is not associated with antiphospholipid antibodies or abnormal coagulation parameters. The significance of such lesions at present remains unclear.


Asunto(s)
Anticuerpos Antifosfolípidos/sangre , Coagulación Sanguínea , Encéfalo/inmunología , Encéfalo/patología , Trastornos Migrañosos/inmunología , Trastornos Migrañosos/patología , Adulto , Femenino , Humanos , Inmunoglobulina D/sangre , Consentimiento Informado , Imagen por Resonancia Magnética , Masculino , Trastornos Migrañosos/sangre , Selección de Paciente , Valores de Referencia
3.
J Exp Clin Cancer Res ; 25(3): 383-90, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17167979

RESUMEN

Recent advances in magnetic resonance imaging (MRI) have allowed the evaluation of metabolic, diffusion and hemodynamic features of malignant gliomas. The aim of this study was to evaluate whether such information provided useful, complementary information to conventional MRI for improving the evaluation of glioblastoma extent. Ten patients with glioblastoma multiforme underwent conventional MRI, proton MR spectroscopic imaging (1H-MRSI), perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI). Metabolite signals, including normalized choline, N-acetylaspartate, creatine and lactate/lipids, were obtained by 1H-MRSI; apparent diffusion coefficient (ADC) by DWI; and relative cerebral blood volume (rCBV) by PWI. In edematous-appearing areas, 3 multiparametric patterns were identified: infiltrating tumor, with abnormal metabolite ratios, lower ADC and higher rCBV; pure edema, with normal metabolite ratios, higher ADC and lower rCBV; and tumor-infiltrated edema, with abnormal metabolite ratios and intermediate ADC and rCBV. In normal-appearing areas, 2 multiparametric patterns were identified: tumor-infiltrated tissue, with abnormal metabolite ratios and higher rCBV; and normal tissue, with normal MR parameters. The combination of 1H-MRSI, DWI and PWI features contributed to delineation of glioblastomas, offering information not available with conventional MRI. This approach may enhance the assessment of brain gliomas, providing useful information for guiding stereotactic biopsies, surgical resection and radiation treatment.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Imagen de Difusión por Resonancia Magnética/métodos , Glioblastoma/diagnóstico , Espectroscopía de Resonancia Magnética/métodos , Edema/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Perfusión
4.
J Neurosurg Sci ; 49(3): 73-6, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16288189

RESUMEN

The radiologic modality that most likely provides the imaging information needed in a patient suspected of having a brain tumors is magnetic resonance imaging. A brain tumors can be reliably ruled out, if the standard magnetic resonance examination is performed properly and experts interpret the results as negative for tumor. In this paper we will illustrate morphological aspects of low-grade supratentorial neoplasms, including tumors of neuroepithelial tissue, such as low-grade diffuse fibrillary astrocytomas, and circumscribed astrocytic lesions (pilocytic astrocytoma, pleomorphic xantoastrocytoma and subependymal giant cell astrocytoma). Then the main practical applications of functional imaging in neurosurgery will be also debated.


Asunto(s)
Glioma/diagnóstico por imagen , Glioma/patología , Imagen por Resonancia Magnética , Neoplasias Supratentoriales/diagnóstico por imagen , Neoplasias Supratentoriales/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Humanos , Radiografía
5.
J Bone Miner Res ; 12(10): 1729-36, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9333135

RESUMEN

Bone involvement is a common clinical feature in acromegalic patients, though previous studies gave divergent results possibly because of the different gonadal status of the patients studied. To study the influence of estrogen milieu in these patients, we evaluated 23 acromegalic patients with active disease, subdivided into two groups: menstruating and amenorrheal patients, comparable for duration and activity of disease. Forty-two matched women served as controls. Skeletal involvement was studied by measuring: (a) the main biomarkers of bone turnover: serum alkaline phosphatase total activity (AP), bone GLA protein (BGP), serum carboxy-terminal propeptide of type I collagen (PICP), serum type I cross-linked N-telopeptide (ICTP), and urinary pyridinoline and deoxypyridinoline corrected for creatinine (Pyr/Cr, D-Pyr/Cr) and urinary calcium/creatinine ratio (Ca/Cr); (b) bone mineral density (BMD), as measured by quantitative computed tomography both at lumbar spine and distal radius, and by dual X-ray absorptiometry both at lumbar spine and at three femoral sites (Ward's triangle, femoral neck, and great trochanter). AP, BGP, ICTP, Pyr/Cr, D-Pyr/Cr were significantly higher in patients than in controls, independent of the menstrual pattern. Higher PICP levels were found in the whole group and in menstruating acromegalics when compared with control women; no difference was found in amenorrheal patients, who in turn showed higher urinary Ca/Cr values. When patients were considered all together, BMD at spine, femoral neck, and trochanter was higher than in controls. In contrast, when the gonadal status was taking into account and, menstruating and amenorrheal subjects were considered separately, BMD at spine, but not in other sites, was significantly higher in menstruating patients than in controls. In contrast, no difference of BMD values at any site was observed between amenorrheal patients and controls. The mean BMD Z scores allowed us to detect an unequal involvement of different skeletal sites. Our results show that bone turnover is increased in acromegalic women and suggest that GH anabolic effect on bone is more evident in the presence of estrogens and that different skeletal sites may be affected differently by hormone excess.


Asunto(s)
Acromegalia/fisiopatología , Amenorrea/fisiopatología , Desarrollo Óseo/fisiología , Hormona del Crecimiento/sangre , Menstruación/fisiología , Acromegalia/sangre , Acromegalia/orina , Adulto , Anciano , Fosfatasa Alcalina/sangre , Aminoácidos/orina , Análisis de Varianza , Biomarcadores/sangre , Biomarcadores/orina , Densidad Ósea/fisiología , Calcio/orina , Creatinina/orina , Estrógenos/sangre , Femenino , Humanos , Factor I del Crecimiento Similar a la Insulina/análisis , Persona de Mediana Edad , Osteocalcina/sangre , Fragmentos de Péptidos/sangre , Procolágeno/sangre
6.
Eur J Radiol ; 28(2): 117-25, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9788013

RESUMEN

PURPOSE: To compare the accuracy of three different magnetic resonance angiography (MRA) techniques for studying steno-occlusive disease of carotid arteries. METHODS: 64 patients were evaluated with three MRA techniques- three-dimensional (3D) time-of-flight (TOF), two-dimensional (2D) TOF, and 3D Phase-Contrast (PC); the acquisition was in the axial plane, the volume included the carotid bifurcation. Digital subtraction angiography (DSA) was considered the 'gold standard'. The MRA images were reprojected with a maximum intensity pixel ray-tracing (MIP) algorithm. The three MRA techniques were blindly graded as normal, mildly stenotic (0-29%), moderately stenotic (30-49%), severely stenotic (70-99%), or occluded. RESULTS: DSA provided 128 diagnostic judgments: 92 were negatives and 36 positives. 2D TOF was in agreement with angiography in 116 of 128 cases (90%), but overestimated the results in seven cases and underestimated in five cases. 3D TOF agreed with angiography in 125 of 128 cases (97%), with one overestimation and two under estimations. 3D PC was concordant in 116 of 128 cases (90%), overestimating in six cases, underestimating in six cases. The sensitivity, specificity and diagnostic accuracy for 2D TOF was, respectively 84%, 94%, and 92%, while for 3D TOF was 94%, 100%, and 98%, and for 3D PC 86%, 98%, and 95%. The comparison of the three different MRA techniques provided no statistically significant difference (Friedman test P < 0.05). CONCLUSION: The high degree of diagnostic accuracy of MRA found in the study of the steno-occlusive disease of the carotid arteries confirms the high degree of reliability of this methodology carried out with the 3D TOF technique, compared to 2D TOF and 3D PC.


Asunto(s)
Estenosis Carotídea/diagnóstico , Angiografía por Resonancia Magnética/métodos , Arterias Carótidas/patología , Humanos , Sensibilidad y Especificidad
7.
Eur J Radiol ; 48(2): 146-53, 2003 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-14680905

RESUMEN

Proton magnetic resonance spectroscopy (1H-MRS) of the brain reveals specific biochemical information about cerebral metabolites, which may support clinical diagnoses and enhance the understanding of neurological disorders. The advantages of performing 1H-MRS at higher field strengths include better signal to noise ratio (SNR) and increased spectral, spatial and temporal resolution, allowing the acquisition of high quality, easily quantifiable spectra in acceptable imaging times. In addition to improved measurement precision of N-acetylaspartate, choline, creatine and myo-inositol, high-field systems allow the high-resolution measurement of other metabolites, such as glutamate, glutamine, gamma-aminobutyric acid, scyllo-inositol, aspartate, taurine, N-acetylaspartylglutamate, glucose and branched amino acids, thus extending the range of metabolic information. However, these advantages may be hampered by intrinsic field-dependent technical difficulties, such as decreased T2 signal, chemical shift dispersion errors, J-modulation anomalies, increased magnetic susceptibility, eddy current artifacts, limitations in the design of homogeneous and sensitive radiofrequency (RF) coils, magnetic field instability and safety issues. Several studies demonstrated that these limitations could be overcome, suggesting that the appropriate optimization of high-field 1H-MRS would expand the application in the fields of clinical research and diagnostic routine.


Asunto(s)
Encéfalo/metabolismo , Espectroscopía de Resonancia Magnética , Algoritmos , Humanos , Espectroscopía de Resonancia Magnética/efectos adversos , Espectroscopía de Resonancia Magnética/métodos , Protones
8.
J Neuroradiol ; 26(2): 87-91, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10444932

RESUMEN

PURPOSE: To determine sensitivity, specificity and diagnostic accuracy of contrast-enhanced magnetic resonance angiography (CE MRA) compared to digital subtraction angiography (DSA) in the study of carotid stenosis. METHODS AND MATERIAL: We studied 23 patients with suspected cerebro-vascular insufficiency by carotid stenosis. Diagnostic examinations by means of CE MRA and DSA were carried out within 24 hours of each other. A 1.5 T superconductive magnet (Signa-General Electric) was used for CE MRA. This technique was performed using a fast spoiled gradient echo recalled (SPGR) sequence acquired in coronal plane 13 sec after injection of contrast medium. Imaging parameters were: TR/TE/FA 8 msec/1 msec/60 degrees, matrix 256 x 128, 1 excitation, FOV 18 x 13 cm, 28 slices per slab, slice thickness of 1 mm, acquisition time of 32 sec. The post-processing was performed using maximum intensity projection (MIP) and targeted MIP. For DSA examinations a Politron 1000 VR unit (Siemens) was used. RESULTS: In the identification and quantification of lesions, CE MRA showed values of 100%. In particular, in comparison to DSA, CE MRA was accurate in diagnosing all true negative and positive cases. The location of stenosis evaluated with CE MRA agreed in all cases with DSA. CONCLUSION: In our experience CE MRA proved to be a very valuable technique in diagnosing carotid stenosis, showing the same diagnostic accuracy as DSA. In this way CE MRA appears to be a substantial alternative technique to conventional MRA and other non-invasive diagnostic methods.


Asunto(s)
Angiografía de Substracción Digital , Estenosis Carotídea/diagnóstico , Angiografía por Resonancia Magnética/métodos , Intensificación de Imagen Radiográfica/métodos , Anciano , Medios de Contraste , Femenino , Humanos , Masculino , Persona de Mediana Edad
9.
Technol Health Care ; 5(5): 375-81, 1997 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9476316

RESUMEN

In a multicenter evaluation the precision and stability of single slice peripheral Quantitative Computed Tomography (pQCT) systems were assessed. Compared to central Europe the peripheral QCT device is also widely used in the Italian health care system. Phantoms were measured frequently on each machine in four pQCT scanners over a two-year period using an identical automated software program. Intrasite and intersite phantom mineral densities, expressed in units of mg/cm3, were analyzed and examined. The short and long term precision were estimated from the consistency of these measurements using the root mean square error and expressed as coefficient of variation in percent (% CV). Short term precision was good (mean intrasite coefficient of variation (CV) 0.21 +/- 0.056 standard deviation (SD)). Intersite measurements of a single phantom revealed differences between machines of the same type of not more than 2.9 mg/cm3. At four sites frequent phantom measurements revealed a mean CV of 0.18% (range 0.12-0.28). No significant changes in the regression slopes (drift of the machine versus time) were observed. We conclude that the in vitro precision and stability of the single slice pQCT systems are sufficiently high and unlikely to negatively affect the in vivo precision.


Asunto(s)
Huesos/diagnóstico por imagen , Fantasmas de Imagen , Tomografía Computarizada por Rayos X/métodos , Absorciometría de Fotón , Densidad Ósea/fisiología , Humanos , Técnicas In Vitro , Modelos Lineales , Reproducibilidad de los Resultados
10.
G Chir ; 10(5): 259-61, 1989 May.
Artículo en Italiano | MEDLINE | ID: mdl-2518563

RESUMEN

Acute pancreatitis is a rare complication of intrabiliary rupture of an hydatid cyst. The Authors report a new case and discuss its clinical, radiological and surgical findings with special emphasis to the diagnostic approach and surgical management.


Asunto(s)
Enfermedades de los Conductos Biliares/etiología , Equinococosis Hepática/complicaciones , Pancreatitis/etiología , Enfermedad Aguda , Enfermedades de los Conductos Biliares/diagnóstico por imagen , Equinococosis Hepática/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Rotura Espontánea
12.
Radiol Med ; 114(3): 461-74, 2009 Apr.
Artículo en Inglés, Italiano | MEDLINE | ID: mdl-19277839

RESUMEN

PURPOSE: This study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented white-matter changes by means of diffusion studies (diffusion-weighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria. MATERIALS AND METHODS: Thirty-two patients with the classical clinical and biochemical deficits of phenylketonuria underwent biochemical (blood phenylalanine), genotypic (phenylalanine hydroxylase gene) and radiological investigation by means of MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging with a 3.0-T scanner. RESULTS: Periventricular and subcortical white-matter changes were detected on all MR scans. In 29/32 patients, proton magnetic resonance spectroscopy easily documented abnormal signal elevation at 7.36 ppm, corresponding to phenylalanine, despite its low concentration. Phenylalanine signal amplitude relative to the creatine/phosphocreatine signal increased linearly with blood phenylalanine values (r 0.7067; p<0.001). Diffusion MRI demonstrated hyperintensity in the areas exhibiting MRI changes as well as decreased apparent diffusion coefficient values, but fractional anisotropy indices were normal. CONCLUSIONS: The high signal, together with better spectral, spatial, contrast and temporal resolution, makes the 3.0-T MR the most suitable technique in the study of the phenylketonuria. In particular, the multimodal approach with MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging can provide more information than previous studies performed with low-field systems.


Asunto(s)
Encéfalo/patología , Imagen de Difusión por Resonancia Magnética , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética , Fenilcetonurias/diagnóstico , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Fenilcetonurias/patología , Sensibilidad y Especificidad
13.
Radiol Med ; 113(1): 134-43, 2008 Feb.
Artículo en Inglés, Italiano | MEDLINE | ID: mdl-18338133

RESUMEN

PURPOSE: This study was performed to clarify the role of perfusion-weighted imaging (PWI) at 3 Tesla in the characterisation of haemodynamic heterogeneity within gliomas and surrounding tissues and in the differentiation of high-grade from low-grade gliomas. MATERIALS AND METHODS: We examined 36 patients with histologically verified gliomas (25 with high-grade and 11 with low-grade gliomas). PWI was performed by first-pass gadopentetate dimeglumine T2*-weighted echo-planar images, and cerebral blood volume (CBV) maps were computed with a nondiffusible tracer model. Relative CBV (rCBV) was calculated by dividing CBV in pathological areas by that in contralateral white matter. RESULTS: In high-grade gliomas, rCBV were markedly increased in mass [mean+/-standard deviation (SD), 4.3+/-1.2] and margins (4.0+/-1.1) and reduced in necrotic areas (0.3+/-0.3). Oedematous-appearing areas were divided in two groups according to signal intensity on T2-weighted images: tumour with lower (nearly isointense to grey matter) and oedema with higher (scarcely isointense to cerebrospinal fluid) signal intensity. Tumour showed significantly higher rCBV than did oedema (1.8+/-0.5 vs. 0.5+/-0.2; p<0.001) areas. In low-grade gliomas, mass (2.0+/-1.5) and margin (2.2+/-1.2) rCBV were significantly lower than in high-grade gliomas (p<0.001). CONCLUSIONS: Three-Tesla PWI helps to distinguish necrosis from tumour mass, infiltrating tumour from oedema and high-grade from low-grade gliomas. It enhances the magnetic resonance (MR) assessment of cerebral gliomas and provides useful information for planning surgical and radiation treatment.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Glioma/diagnóstico , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Adulto , Anciano , Astrocitoma/diagnóstico , Volumen Sanguíneo/fisiología , Edema Encefálico/diagnóstico , Circulación Cerebrovascular/fisiología , Medios de Contraste , Diagnóstico Diferencial , Imagen Eco-Planar/métodos , Femenino , Gadolinio DTPA , Ganglioglioma/diagnóstico , Glioblastoma/diagnóstico , Humanos , Aumento de la Imagen/métodos , Masculino , Persona de Mediana Edad , Necrosis , Oligodendroglioma/diagnóstico , Estudios Retrospectivos
14.
Radiol Med ; 112(1): 82-96, 2007 Feb.
Artículo en Inglés, Italiano | MEDLINE | ID: mdl-17310288

RESUMEN

Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.


Asunto(s)
Encefalopatías/diagnóstico , Encéfalo/anatomía & histología , Procesamiento de Imagen Asistido por Computador/métodos , Angiografía por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/métodos , Artefactos , Encéfalo/irrigación sanguínea , Hemorragia Cerebral/diagnóstico , Líquido Cefalorraquídeo , Medios de Contraste/administración & dosificación , Gadolinio/administración & dosificación , Humanos , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador/instrumentación , Malformaciones Arteriovenosas Intracraneales/diagnóstico , Angiografía por Resonancia Magnética/instrumentación , Imagen por Resonancia Magnética/instrumentación , Factores de Tiempo
15.
Radiol Med ; 112(1): 97-112, 2007 Feb.
Artículo en Inglés, Italiano | MEDLINE | ID: mdl-17310287

RESUMEN

The aim of this paper is to illustrate the technical, methodological and diagnostic features of functional imaging (comprising spectroscopy, diffusion, perfusion and cortical activation techniques) and its principal neuroradiological applications on the basis of the experience gained by the authors in the 5 years since the installation of a high-field magnetic resonance (MR) magnet. These MR techniques are particularly effective at 3.0 Tesla (T) owing to their high signal, resolution and sensitivity, reduced scanning times and overall improved diagnostic ability. In particular, the high-field strength enhances spectroscopic analysis due to a greater signal-to-noise ratio (SNR) and improved spectral, space and time resolution, resulting in the ability to obtain high-resolution spectroscopic studies not only of the more common metabolites, but also--and especially--of those which, due to their smaller concentrations, are difficult to detect using 1.5-T systems. All of these advantages can be obtained with reduced acquisition times. In diffusion studies, the high-field strength results in greater SNR, because 3.0-T magnets enable increased spatial resolution, which enhances accuracy. They also allow exploration in greater detail of more complex phenomena (such as diffusion tensor and tractography), which are not clearly depicted on 1.5-T systems. The most common perfusion study (with intravenous injection of a contrast agent) benefits from the greater SNR and higher magnetic susceptibility by achieving dramatically improved signal changes, and thus greater reliability, using smaller doses of contrast agent. Functional MR imaging (fMRI) is without doubt the modality in which high-field strength has had the greatest impact. Images acquired with the blood-oxygen-level-dependent (BOLD) technique benefit from the greater SNR afforded by 3.0-T magnets and from their stronger magnetic susceptibility effects, providing higher signal and spatial resolution. This enhances reliability of the localisation of brain functions, making it possible to map additional areas, even in the millimetre and submillimetre scale. The data presented and results obtained to date show that 3.0-T morphofunctional imaging can become the standard for high-resolution investigation of brain disease.


Asunto(s)
Encéfalo/fisiología , Imagen de Difusión por Resonancia Magnética/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética/métodos , Artefactos , Ácido Aspártico/análogos & derivados , Ácido Aspártico/análisis , Encefalopatías/diagnóstico , Encefalopatías/fisiopatología , Neoplasias Encefálicas/diagnóstico , Arterias Cerebrales/fisiología , Corteza Cerebral/fisiología , Colina/análisis , Medios de Contraste/administración & dosificación , Creatina/análisis , Humanos , Aumento de la Imagen/métodos , Oxígeno/sangre , Factores de Tiempo , Ácido gamma-Aminobutírico/análisis
16.
J Clin Gastroenterol ; 33(1): 80-1, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11418800

RESUMEN

Gastric cancer is often diagnosed in middle-aged patients undergoing upper gastrointestinal endoscopy for abdominal complaints or constitutional symptoms, such as dyspepsia, vomiting or anorexia, weight loss, anemia, jaundice, and ascites. Sometimes, all of these symptoms may be absent, and gastric cancer is diagnosed after detection of metastases to target organs, such as the liver or lung. In a few rare cases, however, even these metastatic localizations may be absent, and clinical signs are only represented by atypical symptoms caused by neurologic metastatic involvement. We report an exceptionally rare case of gastric cancer in which the only presenting symptoms were headache and dizziness caused by a single cerebellar metastasis.


Asunto(s)
Carcinoma de Células en Anillo de Sello/secundario , Neoplasias Cerebelosas/secundario , Neoplasias Gástricas/diagnóstico , Carcinoma de Células en Anillo de Sello/diagnóstico , Carcinoma de Células en Anillo de Sello/patología , Neoplasias Cerebelosas/diagnóstico , Neoplasias Cerebelosas/patología , Cerebelo/patología , Diagnóstico Diferencial , Gastroscopía , Humanos , Masculino , Persona de Mediana Edad , Estómago/patología , Neoplasias Gástricas/patología
17.
Radiol Med ; 91(3): 174-6, 1996 Mar.
Artículo en Italiano | MEDLINE | ID: mdl-8628925

RESUMEN

This study was aimed at investigating if fast spin echo (FSE) pulse sequences can increase the diagnostic capabilities of MRI in the patients with degenerative disease of the postoperative cervical spine, considering their lower magnetic susceptibility than that of conventional spin echo (SE) sequences. The patient population consisted of 15 patients submitted to diskectomy after Cloward and Caspar. MR images were acquired with a 1.5-T unit (Signa, General Electric) with T2-weighted FSE versus conventional T1- and T2-weighted SE images. Thanks to fewer metallic artifacts, FSE images of the postoperative cervical spine yielded more pieces of information than conventional SE sequences in demonstrating the spine and its content. The best results were obtained in the patients with canal stenosis (8 patients) and myelomalacia (2 patients). In addition, the myelographic effect, another major semiologic feature of the FSE technique, provided further diagnostic information in these patients. Moreover, shorter examination times resulted in better patients tolerance, especially in those with recent surgery. Finally, reducing motion, blood flow or CSF flow artifacts definitely improved FSE image quality.


Asunto(s)
Artefactos , Vértebras Cervicales/patología , Compuestos Férricos , Desplazamiento del Disco Intervertebral/diagnóstico , Imagen por Resonancia Magnética/métodos , Osteofitosis Vertebral/diagnóstico , Anciano , Vértebras Cervicales/cirugía , Femenino , Humanos , Desplazamiento del Disco Intervertebral/cirugía , Imagen por Resonancia Magnética/instrumentación , Masculino , Persona de Mediana Edad , Periodo Posoperatorio , Sensibilidad y Especificidad , Osteofitosis Vertebral/cirugía , Estenosis Espinal/diagnóstico
18.
Radiol Med ; 91(3): 202-6, 1996 Mar.
Artículo en Italiano | MEDLINE | ID: mdl-8628931

RESUMEN

A major application of Magnetic Resonance Imaging (MRI) consists in the "myelographic effect", characterized by high signal intensity of the CSF, which permits to visualize spinal subarachnoid spaces and nerve root sheaths. Such new ultrafast pulse sequences as fast spin echo (FSE) further enhance CSF high signal intensity. In addition, suppressing background with the fat suppression technique and with maximum intensity projection (MIP), a particular algorithm already used in MR angiography, FSE sequences yield 3D myelography-like images. Our study was aimed at assessing the clinical role and the reliability of this technique. Our preliminary experience is based on 21 patients with pain in the lower back and legs and on 5 healthy volunteers; all the myelography-like images were obtained with a 1.5-T MR system (Signa, General Electric). The parameters for FSE myelography-like images included: TR = 6000, TE = 200, ETL = 32, thickness = 3 mm, matrix = 256 x 224, Nex = 4, FOV = 20 cm, fat presaturation, no phase wrap, acquisition time = 2 min 58 s. MR myelography sequences were acquired after a standard FSE T1/T2-weighted exam. MR-myelography results confirmed the diagnosis of disk herniation made on conventional T1/T2-weighted images, especially in thecal sac compression and/or amputation of nerve root sheaths. MR myelography appeared to be especially useful in migrated disk herniation or in abnormal origin of nerve roots. Moreover, it allowed full and panoramic visualization of the subarachnoid spaces and excellent definition of the thecal sac, nerve roots and nerve root sheaths. In one patient only movement artifacts affected image quality. To conclude, even though it fails to yield any functional information, MR myelography appears to be an easy, rapid and noninvasive support to conventional MRI of the lumbar spine, to replace conventional myelography.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Médula Espinal/patología , Femenino , Humanos , Desplazamiento del Disco Intervertebral/complicaciones , Desplazamiento del Disco Intervertebral/diagnóstico , Dolor de la Región Lumbar/diagnóstico , Dolor de la Región Lumbar/etiología , Vértebras Lumbares/patología , Imagen por Resonancia Magnética/instrumentación , Masculino , Persona de Mediana Edad , Ciática/diagnóstico , Ciática/etiología
19.
Radiol Med ; 82(3): 260-4, 1991 Sep.
Artículo en Italiano | MEDLINE | ID: mdl-1947259

RESUMEN

In everyday practice, the radiologist is concerned with the diagnosis of inflammatory conditions of the nose and paranasal sinuses. This paper was aimed at evaluating and comparing the diagnostic efficacy of the main diagnostic imaging procedures currently available. Fifty-six patients were studied: 25 with computed radiography (CR) and CT, 21 with CR and MRI (0.22 T resistive magnet), and 10 with CR, CT, and MRI. From the diagnostic point of view, the conventional-like CR image was assumed as analog to the conventional radiographic (RX) one on the basis of previous personal experience. The following elements were separately considered for RX, CR, CT, and MRI: anatomical structure identificability, spatial resolution, dosimetry, time consumption, diagnostic results, and economics. A global performance index was calculated (RX less than 1; CR = 1; MRI ranging 1.2-2.2; CT = 7.3). CR was superior to RX, from both a diagnostic and a dosimetric point of view, but buying the equipment is nowadays expensive. CT and MRI were superior to both RX and CR in the diagnosis of inflammatory conditions of the nose and paranasal sinuses. When an inflammatory condition is unquestionable, MRI is more accurate than CT, but the latter (thanks to its optimal documentation of both bony walls and soft tissues) is superior to MRI in the differential diagnosis of a generic disease of the nose and paranasal sinuses--that is, when the inflammatory nature is questionable. MRI limitations were poor visualization of bone walls, high cost, and poor access. Thus, CT emerged as the technique of choice, thanks to its diagnostic results, easy access and low cost, with a negligible radiation dose to patients.


Asunto(s)
Imagen por Resonancia Magnética , Rinitis/diagnóstico , Sinusitis/diagnóstico , Tomografía Computarizada por Rayos X , Adulto , Anciano , Humanos , Persona de Mediana Edad
20.
Cardiologia ; 37(9): 627-30, 1992 Sep.
Artículo en Italiano | MEDLINE | ID: mdl-1292867

RESUMEN

A case of an isolated recurrent cardiac hydatidosis with multiple intrapericardial cysts is presented. The patient, who underwent 2 previous surgical resection of intramyocardial and pericardial hydatid cysts, presented with atypical chest pain. The ECG and the perfusion scintigraphy with 201-thallium showed a previous lateral myocardial infarction. The diagnosis of recurrent cardiac hydatidosis was made by two-dimensional echocardiography and computed tomography and was confirmed by clinical and biochemical findings.


Asunto(s)
Cardiomiopatías/diagnóstico , Equinococosis/diagnóstico , Pericardio , Adulto , Cardiomiopatías/cirugía , Equinococosis/cirugía , Ecocardiografía , Electrocardiografía , Humanos , Masculino , Pericardio/diagnóstico por imagen , Pericardio/cirugía , Cintigrafía , Recurrencia , Reoperación , Radioisótopos de Talio , Tomografía Computarizada por Rayos X
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