RESUMEN
PURPOSE: Computed tomography (CT) accounts for more than half of the total radiation exposure from medical procedures, which makes dose reduction in CT an effective means of reducing radiation exposure. We analysed the dose reduction that can be achieved with a new CT scanner [Somatom Edge (E)] that incorporates new developments in hardware (detector) and software (iterative reconstruction). METHODS: We compared weighted volume CT dose index (CTDI(vol)) and dose length product (DLP) values of 25 consecutive patients studied with non-enhanced standard brain CT with the new scanner and with two previous models each, a 64-slice 64-row multi-detector CT (MDCT) scanner with 64 rows (S64) and a 16-slice 16-row MDCT scanner with 16 rows (S16). We analysed signal-to-noise and contrast-to-noise ratios in images from the three scanners and performed a quality rating by three neuroradiologists to analyse whether dose reduction techniques still yield sufficient diagnostic quality. RESULTS: CTDI(Vol) of scanner E was 41.5 and 36.4 % less than the values of scanners S16 and S64, respectively; the DLP values were 40 and 38.3 % less. All differences were statistically significant (p < 0.0001). Signal-to-noise and contrast-to-noise ratios were best in S64; these differences also reached statistical significance. Image analysis, however, showed "non-inferiority" of scanner E regarding image quality. CONCLUSIONS: The first experience with the new scanner shows that new dose reduction techniques allow for up to 40 % dose reduction while still maintaining image quality at a diagnostically usable level.
Asunto(s)
Encefalopatías/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Dosis de Radiación , Protección Radiológica/instrumentación , Protección Radiológica/métodos , Tomografía Computarizada por Rayos X/instrumentación , Tomografía Computarizada por Rayos X/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Diseño de Equipo , Análisis de Falla de Equipo , Femenino , Cabeza/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Intensificación de Imagen Radiográfica/instrumentación , Intensificación de Imagen Radiográfica/métodos , Interpretación de Imagen Radiográfica Asistida por Computador/instrumentación , Interpretación de Imagen Radiográfica Asistida por Computador/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto JovenRESUMEN
QUESTION UNDER STUDY: For the determination of brain death (BD) in potential organ donors, confirmatory tests that show cessation of cerebral circulation are used in many countries. Conventional angiography is considered the golden standard among these ancillary examinations. In recent years other angiographic techniques such as CT angiography (CTA) have been increasingly employed to establish the diagnosis of BD. We report our experience with CTA in this setting. MATERIAL AND METHODS: From 2007 to 2010, 29 patients were examined in order to determine BD using CTA. The studies consisted of an unenhanced head scan, a CT angiogram of the brain supplying vessels in the head and neck and a second head scan 80 seconds after contrast injection (venous phase). The studies were retrospectively re-evaluated by two experienced neuroradiologists according to the criteria accepted by the Swiss Academy of Medical Sciences. RESULTS: In 22 patients, cessation of cerebral circulation was confirmed in the venous phase CT. In seven patients, cessation of brain circulation was not confirmed due to residual contrast enhancement in the relevant cerebral vessels, i.e. the M4-segments of the middle cerebral artery and/or the internal cerebral veins. In these patients, clinical re-evaluation after a minimum of six hours confirmed the diagnosis of BD. Using the clinical examination as the "golden standard," CTA achieved a sensitivity of 75.9%. CONCLUSION: CTA is a useful additional tool for the confirmation of the diagnosis of brain death. Pooling of contrast in the relevant cerebral vessels, however, can be detected in up to 25% of CTAs in clinically brain dead patients.
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Muerte Encefálica/diagnóstico , Angiografía Cerebral , Donantes de Tejidos , Tomografía Computarizada por Rayos X/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/irrigación sanguínea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trasplante de Órganos , Adulto JovenRESUMEN
BACKGROUND AND PURPOSE: Nonconvulsive status epilepticus (NCSE) is associated with a mortality rate of up to 18%, therefore requiring prompt diagnosis and treatment. Our aim was to evaluate the diagnostic value of perfusion CT (PCT) in the differential diagnosis of NCSE versus postictal states in patients presenting with persistent altered mental states after a preceding epileptic seizure. We hypothesized that regional cortical hyperperfusion can be measured by PCT in patients with NCSE, whereas it is not present in postictal states. MATERIALS AND METHODS: Nineteen patients with persistent altered mental status after a preceding epileptic seizure underwent PCT and electroencephalography (EEG). Patients were stratified as presenting with NCSE (n = 9) or a postictal state (n = 10) on the basis of clinical history and EEG data. Quantitative and visual analysis of the perfusion maps was performed. RESULTS: Patients during NCSE had significantly increased regional cerebral blood flow (P > .0001), increased regional cerebral blood volume (P > .001), and decreased (P > .001) mean transit time compared with the postictal state. Regional cortical hyperperfusion was depicted in 7/9 of patients with NCSE by ad hoc analysis of parametric perfusion maps during emergency conditions but was not a feature of postictal states. The areas of hyperperfusion were concordant with transient clinical symptoms and EEG topography in all cases. CONCLUSIONS: Visual analysis of perfusion maps detected regional hyperperfusion in NCSE with a sensitivity of 78%. The broad availability and short processing time of PCT in an emergency situation is a benefit compared with EEG. Consequently, the use of PCT in epilepsy may accelerate the diagnosis of NCSE. PCT may qualify as a complementary diagnostic tool to EEG in patients with persistent altered mental state after a preceding seizure.
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Corteza Cerebral/irrigación sanguínea , Corteza Cerebral/diagnóstico por imagen , Circulación Cerebrovascular , Estado Epiléptico/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Adulto , Anciano , Diagnóstico Diferencial , Electroencefalografía , Servicios Médicos de Urgencia , Epilepsia Generalizada/diagnóstico por imagen , Epilepsia Generalizada/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Cardiovasculares , Estudios Retrospectivos , Estado Epiléptico/fisiopatologíaRESUMEN
PURPOSE: We evaluated the impact of premature extrauterine life on brain maturation. PATIENTS AND METHODS: Twelve neonates underwent MR imaging at 40 (39.64 +/- 0.98) weeks (full term). Fifteen premature infants underwent 2 MR imaging examinations, after birth (preterm at birth) and at 40 weeks (41.03 +/- 1.33) (preterm at term). A 3D MR imaging technique was used to measure brain volumes compared with intracranial volume: total brain volume, cortical gray matter, myelinated white matter, unmyelinated white matter, basal ganglia (BG), and CSF. RESULTS: The average absolute volume of intracranial volume (269.8 mL +/- 36.5), total brain volume (246.5 +/- 32.3), cortical gray matter (85.53 mL +/- 22.23), unmyelinated white matter (142.4 mL +/-14.98), and myelinated white matter (6.099 mL +/-1.82) for preterm at birth was significantly lower compared with that for the preterm at term: the average global volume of intracranial volume (431.7 +/- 69.98), total brain volume (391 +/- 66,1), cortical gray matter (179 mL +/- 41.54), unmyelinated white matter (185.3 mL +/- 30.8), and myelinated white matter (10.66 mL +/- 3.05). It was also lower compared with that of full-term infants: intracranial volume (427.4 mL +/- 53.84), total brain volume (394 +/- 49.22), cortical gray matter (181.4 +/- 29.27), unmyelinated white matter (183.4 +/- 27.37), and myelinated white matter (10.72 +/- 4.63). The relative volume of cortical gray matter (30.62 +/- 5.13) and of unmyelinated white matter (53.15 +/- 4.8) for preterm at birth was significantly different compared with the relative volume of cortical gray matter (41.05 +/- 5.44) and of unmyelinated white matter (43.22 +/- 5.11) for the preterm at term. Premature infants had similar brain tissue volumes at 40 weeks to full-term infants. CONCLUSION: MR segmentation techniques demonstrate that cortical neonatal maturation in moderately premature infants at term and term-born infants was similar.
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Encéfalo/anatomía & histología , Encéfalo/crecimiento & desarrollo , Recien Nacido Prematuro/crecimiento & desarrollo , Imagen por Resonancia Magnética , Humanos , Recién Nacido , Estudios ProspectivosRESUMEN
CT and MRI have the potential to become useful adjuncts to forensic autopsy in the near future. The examination of fatal injuries facilitates a profound experience in the clinical-radiological examination of these cases; the more severe findings in corpses with autopsy verification can help one to understand the tiny signs seen in clinical cases of surviving victims. We present the case of a 44-year-old male diver who died from severe decompression sickness after rapid ascent from approximately 120 m. Post-mortem CT and MRI studies of the brain and spinal cord revealed extensive gas inclusions in cerebral arteries, spinal arteries and cerebrospinal fluid (CSF) spaces, while the intracranial venous sinuses remained unaffected. These findings were confirmed at autopsy. Appropriate imaging techniques can help forensic pathologists to aim their autopsies at findings that might otherwise remain undetected.
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Enfermedad de Descompresión/complicaciones , Buceo/efectos adversos , Embolia Aérea/etiología , Embolia Intracraneal/etiología , Médula Espinal/irrigación sanguínea , Adulto , Enfermedad de Descompresión/patología , Embolia Aérea/patología , Resultado Fatal , Humanos , Embolia Intracraneal/patología , Masculino , Médula Espinal/patologíaRESUMEN
During the treatment of stroke by local intra-arterial thrombolysis (LIT) it is frequently possible to pass the blood clot with a micro-catheter, allowing perfusion of brain tissue distally to the occlusion. This possibility allows for new early treatments of ischaemic brain tissue, even before the blood clot has been removed. One potential new approach to preserve brain tissue at risk may be locally induced endovascular hypothermia. Physical parameters such as the required micro-catheter input pressure, output velocity and flow rates, and a heat exchange model, applicable in the case of a micro-catheter placed within a guiding catheter, are presented. Also, a simple cerebral temperature model is derived that models the temperature response of the brain to the perfusion with coolant fluids. Based on this model, an expression has been derived for the time needed to reach a certain cerebral target temperature. Experimental in vitro measurements are presented that confirm the usability of standard commercially available micro-catheters to induce local hypothermia of the brain. If applied in vivo, the model predicts a local cooling rate of ischaemic brain tissue of 300 g of approximately 1 degrees C in 1 min, which is up to a factor 30-times faster than the time-consuming systemic hypothermia via the skin. Systemic body temperature is only minimally affected by application of local hypothermia, thus avoiding many limitations and complications known in systemic hypothermia.
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Isquemia Encefálica/terapia , Cateterismo , Hipotermia Inducida/métodos , Accidente Cerebrovascular/terapia , Algoritmos , Isquemia Encefálica/complicaciones , Estudios de Factibilidad , Humanos , Modelos Neurológicos , Accidente Cerebrovascular/etiología , Termogénesis/fisiologíaRESUMEN
Intra-arterial thrombolysis (IAT) is the only treatment that has demonstrated benefit in patients with acute basilar artery occlusions (ABAO). IAT may be difficult to perform when access to the occluded basilar artery (BA) is prevented by pathology of the vertebral arteries (VA). We report on two patients with ABAO due to embolism from the dominating VA. Catheter navigation through the occluded VA and thromboaspiration enabled access to the BA. Thromboaspiration alone or in addition to IAT resulted in a complete recanalization of the BA and a favorable clinical outcome. A stent was deployed at the site of the stenosis in the VA either prior to or immediately after BA recanalization.
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Arteria Basilar/cirugía , Embolia Intracraneal/terapia , Stents , Succión , Terapia Trombolítica , Insuficiencia Vertebrobasilar/terapia , Adulto , Femenino , Humanos , Embolia Intracraneal/etiología , Masculino , Persona de Mediana Edad , Insuficiencia Vertebrobasilar/complicacionesRESUMEN
BACKGROUND: The study was performed to elucidate the impact of tumour volume and surgical resection on the long-term outcome of patients with supratentorial, diffuse, World Health Organization (WHO) grade II astrocytomas and oligo-astrocytomas. METHOD: After analysing 79 adult patients consecutively diagnosed between 1991 and 2000, we selected a group of 42 patients treated by surgery without adjuvant therapy. The tumour volume was defined as the whole region of T2-hyperintensity and measured interactively on pre- and postoperative and follow-up Magnetic Resonance Imaging (MRI) using a dedicated imaging software. Volumetric, clinical, and histological data were analysed for correlation with tumour progression (TP), malignant transformation (MT), drop in functional status (DKPS) and overall survival (OS). FINDINGS: Pre- and postoperative tumour volumes, and the involvement of more than one lobe were strongly associated with worse outcome. Preoperative tumour volume was the strongest predictor of OS (p<0.01) and the only predictor of MT (p<0.05). The absolute and relative volumes of tumour removed by surgery were not significantly associated with outcome. CONCLUSIONS. Initial tumour volume, measured as the volume of T2-hyperintensity on MRI, and tumour extension are the strongest predictors of outcome in patients with supratentorial diffuse astrocytic WHO Grade II tumours. The potential benefit of aggressive tumour resection needs to be investigated in a prospective controlled trial.
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Astrocitoma/patología , Astrocitoma/cirugía , Neoplasias Supratentoriales/patología , Neoplasias Supratentoriales/cirugía , Adulto , Femenino , Estudios de Seguimiento , Humanos , Estado de Ejecución de Karnofsky , Masculino , Persona de Mediana Edad , Procesos Neoplásicos , Estudios Retrospectivos , Tasa de Supervivencia , Resultado del TratamientoRESUMEN
Interventional neuroradiological techniques are described, which are used for revascularisation of the intra-extracranial vessels in acute stroke. The results are based on our experience gained during the endovascular treatment of more than 300 patients suffering from acute stroke during the last years. Indication, procedures and results of intraarterial thrombolysis, thrombo-aspiration, percutaneous transluminal angioplasty, and implantation of stents in cases of occlusion or pseudoocclusion of brain supplying vessels are discussed. Furthermore first experiences with new techniques from other centers are presented, e.g., thrombolysis by ultrasound (sonothrombolysis), by angiojet aspiration, and laser evaporation of the thromboembolic occlusion of intra- and extracranial blood vessels.
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Accidente Cerebrovascular/terapia , Enfermedad Aguda , Adulto , Anciano , Angiografía , Animales , Enfermedades de las Arterias Carótidas/complicaciones , Enfermedades de las Arterias Carótidas/diagnóstico , Enfermedades de las Arterias Carótidas/diagnóstico por imagen , Angiografía Cerebral , Revascularización Cerebral , Ensayos Clínicos Controlados como Asunto , Femenino , Fibrinolíticos/administración & dosificación , Fibrinolíticos/uso terapéutico , Estudios de Seguimiento , Humanos , Hipotermia Inducida , Embolia Intracraneal/terapia , Trombosis Intracraneal/terapia , Terapia por Láser , Imagen por Resonancia Magnética , Masculino , Metaanálisis como Asunto , Persona de Mediana Edad , Estudios Multicéntricos como Asunto , Placebos , Activadores Plasminogénicos/administración & dosificación , Activadores Plasminogénicos/uso terapéutico , Pronóstico , Radiología Intervencionista , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/etiología , Terapia Trombolítica , Factores de Tiempo , Tomografía Computarizada por Rayos X , Terapia por Ultrasonido , Activador de Plasminógeno de Tipo Uroquinasa/administración & dosificación , Activador de Plasminógeno de Tipo Uroquinasa/uso terapéuticoRESUMEN
It is impossible to obtain a representative anatomical documentation of an entire body using classical X-ray methods, they subsume three-dimensional bodies into a two-dimensional level. We used the novel multislice-computed tomography (MSCT) technique in order to evaluate a case of homicide with putrefaction of the corpse before performing a classical forensic autopsy. This non-invasive method showed gaseous distension of the decomposing organs and tissues in detail as well as a complex fracture of the calvarium. MSCT also proved useful in screening for foreign matter in decomposing bodies, and full-body scanning took only a few minutes. In conclusion, we believe postmortem MSCT imaging is an excellent vizualisation tool with great potential for forensic documentation and evaluation of decomposed bodies.
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Autopsia/métodos , Interpretación de Imagen Asistida por Computador , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Cambios Post Mortem , Tomografía Computarizada por Rayos X/métodos , Medicina Legal/métodos , Gases , Homicidio , Humanos , Fracturas Craneales/patologíaRESUMEN
We describe and discuss our experience of more than 500 endovascular procedures for revascularisation of acute or chronic occlusion and stenosis of supraaortic vessels using stents in 171 cases. Whereas endovascular treatment of the innominate, subclavian and vertebral arteries are routinely used in atherosclerotic occlusive lesions, carotid stenting is currently being investigated as an alternative treatment to carotid endarterectomy and seems to offer a less invasive, less traumatic and less cost expensive alternative to achieve the goal to prevent stroke. In a subgroup of high surgical risk patients carotid artery stenting with simultaneous embolic protection of the cerebral blood flow by filter systems was even superior to the endarterectomy-treated patients in a prospective, randomized multi-center study (SAPPHIRE): at 30-day follow up the major event rate for the stented group of 156 patients was 5.8% versus 12.6 for the 151 endarterectomy-treated patients.
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Angioplastia de Balón , Arteriopatías Oclusivas/terapia , Tronco Braquiocefálico , Estenosis Carotídea/terapia , Stents , Arteria Subclavia , Arteria Vertebral , Angiografía , Angioplastia de Balón/métodos , Aortografía , Arteriopatías Oclusivas/diagnóstico , Arteriopatías Oclusivas/diagnóstico por imagen , Estenosis Carotídea/diagnóstico , Estenosis Carotídea/diagnóstico por imagen , Estenosis Carotídea/cirugía , Circulación Cerebrovascular , Endarterectomía Carotidea , Estudios de Seguimiento , Humanos , Angiografía por Resonancia Magnética , Estudios Multicéntricos como Asunto , Estudios Prospectivos , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Riesgo , Stents/efectos adversos , Accidente Cerebrovascular/prevención & control , Factores de Tiempo , Tomografía Computarizada por Rayos XRESUMEN
To investigate cortical, basal ganglia and cerebellar activation in patients with arteriovenous malformations (AVMs) involving the motor pathways, we studied ten patients (six male, four female, mean age 30.3 years, range 7.4-44.1) by whole-brain functional magnetic resonance imaging (fMRI) in a 1.5-T scanner with the EPI-BOLD-technique. In seven cases multiple fMRI studies were available, acquired in the course of the multi-session endovascular interventional treatment. Self-paced right- and left-handed finger-tapping tasks were used to invoke activation. In six patients a super-selective amytal test (Wada test) was performed during diagnostic pre-interventional angiography studies. Abnormal cortical activation patterns, with activation of the primary sensorimotor area, the supplementary motor area and/or the cerebellum shifted to unphysiological locations, were found in four patients. In all cases, localization of the AVM could account for the changes from the normal. After endovascular procedures, fMRI demonstrated shifts in the activation pattern in three patients. In the six patients that had undergone fMRI studies and the Wada test, both methods yielded comparable results. The fact that AVMs are structural anomalies for which the brain can partly compensate ('plasticity') was underlined by these results. fMRI is a valuable tool in the pre-therapeutic evaluation and post-interventional follow-up of patients with cerebral AVMs in whom an operation or an endovascular procedure is planned.
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Malformaciones Arteriovenosas Intracraneales/diagnóstico , Malformaciones Arteriovenosas Intracraneales/fisiopatología , Imagen por Resonancia Magnética , Corteza Motora/patología , Corteza Motora/fisiopatología , Adolescente , Adulto , Niño , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , MasculinoRESUMEN
The diagnosis of anterior spinal artery syndrome can be made with high accuracy by thorough clinical examination in combination with typical magnetic resonance imaging findings. Sudden onset of tetra- or paraparesis and dissociated sensory loss with bladder dysfunction are the leading clinical signs. We discuss clinical and radiologic findings in an adolescent presenting with anterior spinal artery syndrome. The laboratory results showed a hereditary protein S deficiency.
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Síndrome de la Arteria Espinal Anterior/diagnóstico , Síndrome de la Arteria Espinal Anterior/etiología , Deficiencia de Proteína S/complicaciones , Médula Espinal/patología , Adolescente , Síndrome de la Arteria Espinal Anterior/fisiopatología , Diagnóstico Diferencial , Predisposición Genética a la Enfermedad , Humanos , Imagen por Resonancia Magnética , Masculino , Paraplejía/etiología , Trombosis/etiologíaRESUMEN
Each hemisphere is known to be also involved in controlling the ipsilateral arm, but with an asymmetry favoring the dominant hemisphere. However, the relative role of primary and secondary motor areas in ipsilateral control is not well defined. We used whole brain functional magnetic resonance imaging in healthy human subjects to differentiate between contributions from primary and secondary areas during discrete unilateral distal finger and proximal shoulder movements. It was found that ipsilateral distal movements activated secondary areas only, while sparing or even significantly deactivating the primary sensorimotor cortex. Ipsilateral proximal movements substantially activated both SM1 and secondary areas. A newly defined small territory within the precentral gyrus, extending from the premotor cortex and intruding toward SM1, showed an activation pattern corresponding to secondary motor areas. Finally, the effects of hemispheric dominance were confirmed, but attributed exclusively to secondary areas. These new imaging findings agree well with functional requirements as well as established anatomical and neurophysiological data.
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Brazo/inervación , Dominancia Cerebral/fisiología , Procesamiento de Imagen Asistido por Computador , Pierna/inervación , Imagen por Resonancia Magnética , Actividad Motora/fisiología , Corteza Motora/fisiología , Corteza Somatosensorial/fisiología , Adulto , Anciano , Nivel de Alerta/fisiología , Atención/fisiología , Mapeo Encefálico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Destreza Motora/fisiología , Vías Nerviosas/fisiología , Lóbulo Parietal/fisiologíaRESUMEN
In order to investigate the neuronal network involved in processing extraretinal signals, functional magnetic resonance imaging (fMRI) was applied to subjects performing the double step saccade paradigm. There, the calculation of the amplitude of the second saccade must rely on extraretinal signals of the first. When compared to a task where both saccades could be performed by means of retinal signals alone, a parieto-frontal cortical network was activated, including lateral intraparietal area, precuneus, insula, inferior frontal gyrus and anterior cingulum.