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1.
Acta Neurochir Suppl ; 135: 115-118, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38153458

RESUMEN

Chronic subdural hematoma (cSDH) is defined as a subdural collection of blood on CT imaging that tends to persist and gradually increase in volume over time, with components that are hypodense or isodense compared to the brain. There are no proven guidelines for the management of patients with cSDH. Surgical approaches included burr hole, twist drill hole, and craniotomy-based evacuations. Outcomes after surgical removal is generally favorable, but cSDH tends to recur after the initial evacuation.Middle meningeal artery (MMA) embolization has been gaining increasing popularity among the treatments of cSDH. This is largely due to a growing population of patients with cSDH who are refractory to other treatments or in patients who present with multiple comorbidities or who are taking antiplatelet and anticoagulant medications. The goal of middle meningeal artery (MMA) embolization is to devascularize subdural membranes associated with SDH so that the balance between continued leakage and reabsorption is shifted toward reabsorption.We discuss our clinical and technical approach to cSDH treated with perioperative embolization of the MMA.


Asunto(s)
Embolización Terapéutica , Hematoma Subdural Crónico , Humanos , Hematoma Subdural Crónico/diagnóstico por imagen , Hematoma Subdural Crónico/terapia , Arterias Meníngeas/diagnóstico por imagen , Encéfalo , Anticoagulantes
2.
AJNR Am J Neuroradiol ; 42(5): 896-903, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33664106

RESUMEN

BACKGROUND AND PURPOSE: Successful vessel recanalization in posterior circulation large-vessel occlusion is considered crucial, though the evidence of clinical usefulness, compared with the anterior circulation, is not still determined. The aim of this study was to evaluate predictors of favorable clinical outcome and to analyze the effect of first-pass thrombectomy. MATERIALS AND METHODS: A retrospective, multicenter, observational study was conducted in 10 high-volume stroke centers in Europe, including the period from January 2016 to July 2019. Only patients with an acute basilar artery occlusion or a single, dominant vertebral artery occlusion ("functional" basilar artery occlusion) who had a 3-month mRS were included. Clinical, procedural, and radiologic data were evaluated, and the association between these parameters and both the functional outcome and the first-pass effect was assessed. RESULTS: A total of 191 patients were included. A lower baseline NIHSS score (adjusted OR, 0.77; 95% CI, 0.61-0.96; P = .025) and higher baseline MR imaging posterior circulation ASPECTS (adjusted OR, 3.01; 95% CI, 1.03-8.76; P = .043) were predictors of better outcomes. The use of large-bore catheters (adjusted OR, 2.25; 95% CI, 1.08-4.67; P = .030) was a positive predictor of successful reperfusion at first-pass, while the use of a combined technique was a negative predictor (adjusted OR, 0.26; 95% CI, 0.09-0.76; P = .014). CONCLUSIONS: The analysis of our retrospective series demonstrates that a lower baseline NIHSS score and a higher MR imaging posterior circulation ASPECTS were predictors of good clinical outcome. The use of large-bore catheters was a positive predictor of first-pass modified TICI 2b/3; the use of a combined technique was a negative predictor.


Asunto(s)
Arteriopatías Oclusivas/cirugía , Accidente Cerebrovascular/cirugía , Trombectomía/métodos , Anciano , Anciano de 80 o más Años , Arteriopatías Oclusivas/complicaciones , Arteria Basilar/patología , Catéteres , Procedimientos Endovasculares/instrumentación , Procedimientos Endovasculares/métodos , Europa (Continente) , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reperfusión/métodos , Estudios Retrospectivos , Accidente Cerebrovascular/etiología , Trombectomía/instrumentación , Resultado del Tratamiento , Insuficiencia Vertebrobasilar/complicaciones , Insuficiencia Vertebrobasilar/cirugía
3.
Radiol Med ; 126(3): 484-493, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32902826

RESUMEN

PURPOSE: To compare size and morphologic features of three-dimensional aneurysm models, obtained with a semi-automated segmentation software (Stroke VCAR, GE, USA) from cerebral CT angiography (CTA) data, to three-dimensional aneurysm models obtained with digital subtraction angiography (DSA, with 3D rotational angiography acquisition-3DRA), considered as the reference standard. METHODS: In this retrospective study, we reviewed 132 patients, with a total number of 137 intracranial aneurysm, who underwent CTA and subsequent DSA examination, supplemented with 3DRA. We compared neck length, short axis and long axis measured on 3DRA model to the same variables measured on 3D-CTA model by two blinded readers and to the automatic software dimensions. Therefore, statistics analysis assessed intra-observer and inter-observer variability and differences between patients with or without subarachnoid hemorrhage (SAH). RESULTS: There were no significant differences in short-axis and long-axis measurements between 3D angiographic and 3D-CTA models, while comparison of neck lengths revealed a statistically significant difference, which tended to be greater for smaller neck lengths (partial volume effect and "kissing vessels" artifact). There were significant differences between manual and automatic data measured for the same three variables, and the presence of SAH did not affect aneurysm 3D reconstruction. Inter-observer agreement resulted moderate for neck length and substantial for short axis and long axis. CONCLUSION: The examined 3D-CTA segmentation system is a reproducible procedure for aneurysm morphologic characterization and, in particular, for assessment of aneurysm sac dimensions, but considerable carefulness is required in neck length interpretation.


Asunto(s)
Angiografía de Substracción Digital/métodos , Angiografía por Tomografía Computarizada/métodos , Aneurisma Intracraneal/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Angiografía Cerebral/métodos , Femenino , Humanos , Aneurisma Intracraneal/patología , Masculino , Persona de Mediana Edad , Tomografía Computarizada Multidetector/métodos , Variaciones Dependientes del Observador , Estándares de Referencia , Reproducibilidad de los Resultados , Estudios Retrospectivos , Estadísticas no Paramétricas , Hemorragia Subaracnoidea/diagnóstico por imagen , Adulto Joven
4.
Diagn Interv Imaging ; 98(4): 307-314, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27671861

RESUMEN

PURPOSE: The purpose of this study was to define the feasibility, the efficacy and the safety of preoperative embolization (POE) of meningiomas using polyvinyl alcohol (PVA) particles. MATERIALS AND METHODS: Between January 2006 and June 2014, 191 consecutive patients were referred to our institution for the treatment of meningiomas; of these 57 patients were excluded from the study. A total of 64 patients (22 men and 42 women) with a mean age of 58.4±10.8 [SD] years (range: 14-82years) who underwent POE with PVA particles, achieving extensive (>90%) devascularization were ultimately included and compared to 70 patients who had surgery without POE. Surgical time and intraoperative blood loss were compared between the two groups. The duration of procedures and complications related to POE were analyzed. RESULTS: No differences were found between the two groups with respect to intraoperative blood loss. A significant reduction in surgical time was observed for the group who had POE (207.4±79.5 [SD] min vs. 226.9±117.6 [SD] min; P=0.028). In a subgroup analysis, the size and location of meningiomas did not influence these results. The duration of procedures was 41.4±10.5 [SD] min. Minor complications related to POE occurred in 3 out of 64 patients (4.7%). CONCLUSION: POE of meningiomas using PVA particles is effective in reducing surgical time, when extensive tumor devascularization is achieved. However, radiation exposure, the duration of procedures and complications related to POE with PVA particles do not justify this technique in most patients.


Asunto(s)
Embolización Terapéutica , Neoplasias Meníngeas/cirugía , Meningioma/cirugía , Terapia Neoadyuvante , Cuidados Preoperatorios , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Pérdida de Sangre Quirúrgica/fisiopatología , Terapia Combinada , Estudios de Factibilidad , Femenino , Humanos , Masculino , Neoplasias Meníngeas/irrigación sanguínea , Meningioma/irrigación sanguínea , Persona de Mediana Edad , Tempo Operativo , Alcohol Polivinílico , Adulto Joven
5.
Radiol Med ; 118(3): 415-30, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22872461

RESUMEN

PURPOSE: The authors evaluated the usefulness of three-dimensional rotational angiography (3DRA) in surgical planning and postoperative evaluation of cerebral aneurysms. MATERIALS AND METHODS: A total of 111 consecutive aneurysms in 100 patients (32 emergency referrals due to haemorrhage) were evaluated with 3DRA over a period of 3 years. The rotational study was always performed with a single injection of 20 cc of contrast agent in the afferent vessel after diagnostic cerebral angiography in the two orthogonal projections. Three-dimensional reconstructions were obtained for the pre- and postoperative assessment. RESULTS: Three-dimensional RA provides a virtual view of the surgical field with the same orientation required for the surgical approach and, compared with surgical findings, reliably defined location, orientation, morphology and relationship with parent vessels of the aneurysm in all cases. Postoperatively, it allowed better assessment of any residual lesion and of the relationship between surgical clips and parent vessels, compared with standard 2D angiography. CONCLUSIONS: 3DRA is a reliable method for preliminary assessment of cerebral aneurysms undergoing surgery. It provides multiple projections with a preview of the surgical field and study of lesion characteristics, which can help achieve faster and safer surgery. Compared with 2D angiography, the 3D model, with its multiple views, allows better assessment of postoperative outcomes. The method also significantly reduces the number of angiographic projections and therefore radiation and contrast-medium dose to the patient.


Asunto(s)
Angiografía Cerebral/métodos , Imagenología Tridimensional/métodos , Aneurisma Intracraneal/diagnóstico por imagen , Aneurisma Intracraneal/cirugía , Análisis de Varianza , Medios de Contraste , Craneotomía , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Rotación
6.
Radiol Med ; 114(7): 1141-58, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19774443

RESUMEN

PURPOSE: Percutaneous vertebroplasty (PVP) is a minimally invasive treatment for symptomatic vertebral compression fractures (VCFs). The aim of this study was to assess the effectiveness, complications and progress of results of PVP optimized in terms of technique, costs, time and strategic protocol after 3 years of procedures performed under fluoroscopic guidance alone. MATERIALS AND METHODS: We treated 250 VCFs in 120 consecutive patients after assessing clinical and radiological indications. The effectiveness of the procedure was determined by statistical analysis of numerical scores for pain, mobility and drug consumption before and after treatment. RESULTS: No major complications and only three minor complications occurred. Clinically relevant improved mobility and reduction of pain and analgesics were observed, with overall significant results (p<0.0001) in all patients at 24 h after PVP and in 83 available patients at 6 months. A total of five asymptomatic refractures of cemented vertebrae and 14 new symptomatic vertebral fractures at different levels were observed between 1 and 10 months after the procedure. CONCLUSIONS: PVP is a safe, rapid, effective and costeffective therapy for VCFs, requiring only brief hospital admission and with long-lasting clinical results, when performed under good-quality radiological guidance, when correct indications are respected and when it is associated with rehabilitation therapy in the follow-up. It is a valid alternative to conservative therapy, which is burdened by high healthcare costs and often requires long-term immobilisation of frail and elderly patients at risk of clinical complications.


Asunto(s)
Fracturas por Compresión/diagnóstico por imagen , Fracturas por Compresión/cirugía , Fotofluorografía , Radiografía Intervencional , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/cirugía , Vertebroplastia/métodos , Anciano , Anciano de 80 o más Años , Cementos para Huesos/uso terapéutico , Femenino , Fijación Interna de Fracturas/métodos , Fracturas por Compresión/etiología , Fracturas por Compresión/terapia , Humanos , Masculino , Persona de Mediana Edad , Procedimientos Ortopédicos/métodos , Osteoporosis/complicaciones , Dimensión del Dolor/métodos , Fotofluorografía/métodos , Calidad de Vida , Reoperación , Estudios Retrospectivos , Medición de Riesgo , Fracturas de la Columna Vertebral/etiología , Fracturas de la Columna Vertebral/rehabilitación , Fusión Vertebral/métodos , Neoplasias de la Columna Vertebral/complicaciones , Columna Vertebral/diagnóstico por imagen , Columna Vertebral/cirugía , Resultado del Tratamiento
7.
Intensive Care Med ; 34(11): 2100-5, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18618096

RESUMEN

OBJECTIVE: Ultrasound guidance (USG) for internal jugular cannulation is the best solution in difficult settings where paediatric patients are involved. This is an outcome study on efficacy and complications of the USG for the internal jugular vein (IJV) cannulation in neurosurgical infants as well as an ultrasound study of anatomical findings of the IJVs in infants. DESIGN AND SETTINGS: A prospective study conducted in two Academic Neurosurgical hospitals. PARTICIPANTS: In 191 babies (body weight <15 kg), anatomical findings were studied. We performed CVC echo guided placement in 135/191 infants (weighting <10 kg). RESULTS: After a brief training period, both institutions adopted a common protocol and USG device. We obtained successful cannulation in all patients. Carotid puncture (1.5%) was the only main complication registered and minor complications were poor. Time required for cannulation was 12.5 +/- 5.7 min. Anatomical findings (in 191 patients) were IJV laterality in 34.6% cases, IJV antero-lateral in 59.7% and anterior in 5.7%. A linear relation was found between weight and internal jugular vein diameter even if R(2) = 0.43 and the model cannot be used to predict the exact size of the vein. In 62/135 babies weighting <10 kg, anatomical measurements were done in supine and Trendelemburg position. Trendelemburg position increases significantly (P < 0.001) IJV diameter, but not IJV depth. CONCLUSIONS: We considered ultrasound guidance as the first choice in infants because it can enhance IJV cannulation success, safety, and allows one to measure relationships and diameter of the IJV and optimise the central line positioning.


Asunto(s)
Cateterismo Venoso Central/métodos , Venas Yugulares/cirugía , Ultrasonografía Intervencional , Cateterismo Venoso Central/efectos adversos , Femenino , Humanos , Lactante , Recién Nacido , Venas Yugulares/diagnóstico por imagen , Modelos Logísticos , Masculino , Procedimientos Neuroquirúrgicos , Estudios Prospectivos , Punciones , Seguridad
8.
Radiol Med ; 112(6): 895-905, 2007 Sep.
Artículo en Inglés, Italiano | MEDLINE | ID: mdl-17891340

RESUMEN

PURPOSE: The aim of this study was to assess the value of the systematic use of 3D rotational angiography (3DRA) in the diagnosis and preoperative evaluation of cerebral aneurysms with a view to planning endovascular embolisation. MATERIALS AND METHODS: Thirty-five consecutive aneurysms (20 incidental and 15 after subarachnoid haemorrhage) were studied and treated by means of 3DRA over a 1-year period. All rotational studies were conducted by selective cannulation of the vessel supplying the lesion (internal carotid artery or vertebral artery) with a single injection of 20 cc of contrast agent after diagnostic angiography in anterior-posterior (AP) and laterolateral (LL) views. Three-dimensional reconstructions were generated within a mean time of 5 min, and coil embolisation was performed on the basis of the 3D images. RESULTS: Three-dimensional RA enabled accurate definition of site, orientation, morphology and size of the sac and its relationship with the parent arteries and helped us choose the most appropriate angulation of the C-arm for guiding and controlling the embolisation procedure. Furthermore, the technique allowed us to detect six aneurysms for which conventional imaging had yielded equivocal results. CONCLUSIONS: Based on our experience before RA equipment became available and in agreement with the literature, we believe that 3DRA improves the identification of all lesions and helps refine the choice of the most suitable embolisation material and technique. Three-dimensional RA requires substantially fewer projections and thus reduces radiation dose and volume of contrast material to the patient. The use of 3DRA most likely results in a shorter procedure time and fewer risks and complications for the patient.


Asunto(s)
Angiografía Cerebral , Imagenología Tridimensional , Aneurisma Intracraneal/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Lactante , Aneurisma Intracraneal/cirugía , Masculino , Persona de Mediana Edad
9.
Childs Nerv Syst ; 20(8-9): 576-86, 2004 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15309474

RESUMEN

OBJECT: A case of two female Greek twins conjoined at the left frontal and orbital regions is described. These conjoined twins were transferred to the Pediatric Neurosurgical Unit of the Gemelli Hospital, Catholic University Medical School, at the age of 4 months for possible surgical division. METHOD: Multiple diagnostic investigations, which included in particular advanced imaging techniques, demonstrated an independent cerebral vascularization of the two babies and excluded significant intracranial malformations. Such an accurate evaluation of the anatomy of the craniopagus at the level of the cranial junction allowed the feasibility of the surgical correction to be established. CONCLUSIONS: The operation was carried out by a multidisciplinary team in a single stage. The operating team included two distinct teams of neurosurgeons and anesthesiologists as well as a plastic surgeons' team. Both babies survived the operation. The postoperative course was uneventful. Both twins were discharged in good clinical and neurological condition after a 3-week period of hospitalization.


Asunto(s)
Encéfalo/anomalías , Cráneo/anomalías , Gemelos Siameses , Encéfalo/patología , Encéfalo/cirugía , Femenino , Grecia , Humanos , Imagenología Tridimensional/métodos , Lactante , Italia , Imagen por Resonancia Magnética/métodos , Neurocirugia/métodos , Cráneo/patología , Cráneo/cirugía , Cirugía Plástica/métodos , Resultado del Tratamiento , Gemelos Siameses/patología , Gemelos Siameses/cirugía , Ultrasonografía Prenatal/métodos
13.
Rays ; 26(4): 247-68, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-12696280

RESUMEN

The role of diagnostic imaging in the study of atherosclerosis of carotid and intracranial vessels is analyzed, after the illustration of the main characteristics of the disease. Atherosclerosis should be considered a systemic disease, however it tends to be segmental. The commonest sites are the coronary artery, the superficial femoral artery, the subrenal aorta and the carotid arteries at the level of the bifurcation. Traditionally, the percentage of intraluminal stenosis has represented the standard measurement of the severity of atheromatosis. However, the grade of stenosis is not the only sign predictive of clinical complications. The most vulnerable plaques show predominant core necrosis or hemorrhage, separated from the vascular lumen by a thin unstable fibrous cap. The two major aspects of lesions at high risk of rupture are the presence of a large soft core and the status of the fibrous cap that can be intact, ruptured or infiltrated by inflammatory cells. Imaging procedures should be addressed to the identification of these pathologic conditions predisposing to the embolic-thrombotic complication. However, additional information on blood flow dynamics, vascular collateral compensation and brain perfusion is useful for decision-making about the therapeutic approach. This is the reason why in diagnostic imaging of atheromatosis, digital angiography should be combined with color Doppler-US, CT and MRI.


Asunto(s)
Arteriosclerosis/diagnóstico , Estenosis Carotídea/diagnóstico , Enfermedades Arteriales Cerebrales/diagnóstico , Circulación Cerebrovascular , Diagnóstico por Imagen , Velocidad del Flujo Sanguíneo , Arteria Carótida Externa/patología , Arteria Carótida Interna/patología , Humanos
15.
Rays ; 25(4): 399-417, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11367910

RESUMEN

From Herophilus, Aristotle in the 3rd century BC, Aselli, Pecquet, Mascagni to Jossifow and Rouviere the lymphatic system was investigated. Kinmonth and Wallace were the first to study it with lymphangiography. Mediastinal lymph nodes were poorly visualized in high contrast radiography before the seventies; subsequently with the high voltage technique, xerography and signs from mediastinal lines they were better identified. However these procedures were replaced by CT, with which even lymph nodes less than 0.5 cm in size, are recognized. The differentiation between normal and pathologic lymph nodes is based on dimensional, morphologic and densitometric criteria. CT is able to identify typical patterns of inflammatory, systemic and metastatic lymph nodes. On lymphography a great number of signs as gross and dense dotting, foaming, chipping and lacunae are identified, which allow the differentiation of inflammatory, systemic and metastatic patterns. On sonography some nodal characteristics are evidenced as the round shape, hypoechogenicity, absence of hyperechoic medullary line. CT has replaced lymphangiography in the study of abdominal lymph nodes.


Asunto(s)
Linfografía , Humanos , Mediastino , Tomografía Computarizada por Rayos X
16.
Acta Biomed Ateneo Parmense ; 71 Suppl 1: 563-6, 2000.
Artículo en Italiano | MEDLINE | ID: mdl-11424807

RESUMEN

Vertical transmission of HIV is by far the most important way of infection in pediatric patients. Transmission rate of infection varies between 15-40% in the absence of antiretroviral prophylaxis. Only 2% of infected pregnant women who underwent caesarean section and zidovudine treatment transmitted the infection to their newborns. From January 1995 to September 2000 twenty seropositive pregnant women and their twenty newborns were followed at the Azienda Ospedaliera of Parma. Nine women (45%) were treated with only zidovudine according to the ACTG 076 protocol; eight women (40%) continued the treatment they were assuming before pregnancy with the eventual addition of zidovudine. 3 women (15%) were not treated because HIV infection was only detected after delivery. 15 women underwent caesarean section, in 13 cases in association to antiretroviral prophylaxis: in the remaining 2 cases no intrapartum treatment was started due to the urgency of delivery. The rate of vertical transmission among the 20 women was 5% (1/20), significantly less then that observed (20.5%) among 31 pregnant HIV women followed in Parma from January 1987 to December 1994 and not treated with antiretroviral prophylaxis and/or cesarean section (Magnani G. Personal data). The only infected baby was born by vaginal delivery. No transmission was observed in the group of pregnant women who underwent the combination of antiretroviral prophylaxis and cesarean section.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Cesárea , Infecciones por VIH/transmisión , Transmisión Vertical de Enfermedad Infecciosa/estadística & datos numéricos , Zidovudina/uso terapéutico , Femenino , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Humanos , Recién Nacido , Italia , Embarazo , Estudios Retrospectivos , Factores de Riesgo
18.
Radiol Med ; 96(5): 492-7, 1998 Nov.
Artículo en Italiano | MEDLINE | ID: mdl-10051874

RESUMEN

INTRODUCTION: The spreading of interventional procedures and the frequent use and replacement of central venous catheters have contributed to a relative increase in the occurrence of intravascular foreign bodies (FBs). Their retrieval is justified by potential complications related to their characteristics, location and permanence. The high morbidity related to surgical retrieval, especially in case of intravenous FBs (often located in the right cardiac chambers or the pulmonary artery) has contributed to the spreading of interventional retrieval procedures. The purpose of percutaneous retrieval is: 1) to hook the FB to stop its migration to more critical districts; 2) to extract it through the percutaneous access route or, if the latter is unfeasible, 3) to simplify surgical retrieval. MATERIAL AND METHODS: We report our experience with 15 patients presenting an FB [intravenous (i.v.) in 11 cases and intra-arterial (i.a.), in 4]. Retrieval was performed mainly with snare-loop catheters (13 cases, together with a pig-tail catheter in 3 patients) and also with Dormia baskets (3 cases, together with a snare loop in 1 case). To ensure the percutaneous retrieval, we used introductors with a greater caliber than that of the FB, the latter generally being a 6-7 F intravenous catheter. The percutaneous approach was mostly transfemoral (right femoral in 9 cases and bilateral femoral, left femoral, axillary and left jugular in 1 case each). RESULTS: Percutaneous retrieval was successful in all the i.v. cases and in 1 ia case. The other 3 ia cases required surgical removal under local anesthesia after percutaneous hooking and displacement of the FB to a more accessible site. No major complications were observed during retrievals. CONCLUSIONS: Based on our personal results and in agreement with the major international reports, we believe that percutaneous retrieval should be considered the treatment of choice for FBs. The procedure success depends on an accurate diagnostic approach, good knowledge of materials and techniques and the operator's experience, as well as the possibility of an interdisciplinary collaboration of the interventional radiologist with the surgeon and anesthesist.


Asunto(s)
Vasos Sanguíneos , Cateterismo/instrumentación , Cuerpos Extraños/terapia , Adulto , Anciano , Diseño de Equipo , Femenino , Humanos , Masculino , Persona de Mediana Edad
19.
Rays ; 22(2): 295-312, 1997.
Artículo en Inglés, Italiano | MEDLINE | ID: mdl-9351333

RESUMEN

Magnetic Resonance (MR) images sensitive to the flowing blood are defined as images of MR angiography. Proton movement within a magnetic field modifies both the intensity and the phase of Nuclear Magnetic Resonance (NMR) signal; two techniques of MR angiography are thus distinguished: (TOF) the "time of flight" (intensity) and the "phase-contrast" (phase) technique. In the time of flight MR angiography the blood may appear as hypointense or hyperintense compared to stationary tissues. Blood hypointensity in vessels is due to the flow void phenomenon while hyperintensity is due to the phenomenon of flow-related enhancement. In phase contrast MR angiography, protons moving within a magnetic field modify their phase directly proportional to the displacement velocity and gradient intensity. Moreover, MRI allows noninvasive measurement of blood flow. Flow velocity is measured with TOF sequences or phase-contrast sequences. In TOF sequences quantitative measurement is performed with the bolus tracking procedure. In contrast-phase sequences the velocity is measured based on the extent of signal phase modification induced by the proton displacement velocity. The recent use of liver-specific contrast media supplies information on parenchymal liver function.


Asunto(s)
Circulación Hepática/fisiología , Hepatopatías/patología , Hígado/irrigación sanguínea , Angiografía por Resonancia Magnética , Velocidad del Flujo Sanguíneo , Medios de Contraste , Arteria Hepática/fisiología , Humanos , Hepatopatías/diagnóstico , Angiografía por Resonancia Magnética/métodos , Vena Porta/fisiología
20.
Rays ; 22(1): 14-37, 1997.
Artículo en Inglés, Italiano | MEDLINE | ID: mdl-9145013

RESUMEN

In functional radiology of the lung, the depiction of subtle details of circulatory and bronchial anatomy, is very important. At present, the evolution of the radiographic techniques allows to overcome the difficulty in imaging, essentially related to the marked difference in density of chest structures, producing radiographs optimized to the concomitant representation of the parenchyma and higher absorption structures. Main quality factors related to radiation beam optimization on one hand and to imaging systems on the other hand, are considered with an analysis of the evolution of methods and techniques of thoracic radiology.


Asunto(s)
Pulmón/diagnóstico por imagen , Intensificación de Imagen Radiográfica/tendencias , Radiografía Torácica/instrumentación , Medios de Contraste , Humanos , Radiografía Torácica/tendencias , Tecnología Radiológica/instrumentación , Tecnología Radiológica/tendencias
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