Papel del estudio radiológico multimodal en el código ictus / The role of multimodal imaging in stroke code patients

El estudio multimodal engloba distintas técnicas radiológicas utilizadas en el "código ictus". Incluye tomografía computarizada (TC) basal, resonancia magnética (RM) y RM por difusión, técnicas de perfusión con TC o RM y angiografía por TC o RM. Se emplean para descartar sangrado, confirmar oclusión arterial, establecer viabilidad tisular y ayudar a seleccionar a los candidatos a tratamiento endovascular lo antes posible. Se han publicado recientemente cinco relevantes ensayos clínicos que han demostrado la eficacia de la trombectomía mecánica en oclusiones arteriales proximales. Todos han utilizado diferentes estrategias de imagen para la selección de los pacientes. Analizando estos ensayos y la bibliografía científica actual concluimos que la TC convencional con valoración de la puntuación ASPECTS y la angiografía por TC o RM debe usarse siempre, con nivel de evidencia I y grado de recomendación A. Los estudios de perfusión por TC y RM tienen utilidad en situaciones específicas (AU)

In stroke code patients, multimodal imaging workup encompasses various imaging techniques, including baseline computed tomography (CT), magnetic resonance (MR) imaging, diffusion MR imaging, CT or MR perfusion studies, and CT or MR angiography, that are used to rule out bleeding, confirm arterial occlusion, establish tissue viability, and help select candidates for endovascular treatment as early as possible. Five recently published relevant clinical trials have demonstrated the efficacy of mechanical thrombectomy in proximal arterial occlusions; all these trials used different imaging techniques to select patients. Analyzing these trials and the scientific literature, we conclude that conventional CT interpreted with the Alberta Stroke Programme Computed Tomography Score (ASPECTS) and CT or MR angiography should always be used (level of evidence I, grade of recommendation A) and that CT and MR perfusion studies are useful in specific circumstances (AU)

The role of multimodal imaging in stroke code patients. / Papel del estudio radiológico multimodal en el código ictus.

In stroke code patients, multimodal imaging workup encompasses various imaging techniques, including baseline computed tomography (CT), magnetic resonance (MR) imaging, diffusion MR imaging, CT or MR perfusion studies, and CT or MR angiography, that are used to rule out bleeding, confirm arterial occlusion, establish tissue viability, and help select candidates for endovascular treatment as early as possible. Five recently published relevant clinical trials have demonstrated the efficacy of mechanical thrombectomy in proximal arterial occlusions; all these trials used different imaging techniques to select patients. Analyzing these trials and the scientific literature, we conclude that conventional CT interpreted with the Alberta Stroke Programme Computed Tomography Score (ASPECTS) and CT or MR angiography should always be used (level of evidence I, grade of recommendation A) and that CT and MR perfusion studies are useful in specific circumstances.

Diagnostic reference levels and complexity indices in interventional radiology: a national programme.

OBJECTIVES: To propose national diagnostic reference levels (DRLs) for interventional radiology and to evaluate the impact of the procedural complexity on patient doses. METHODS: Eight interventional radiology units from Spanish hospitals were involved in this project. The participants agreed to undergo common quality control procedures for X-ray systems. Kerma area product (KAP) was collected from a sample of 1,649 procedures. A consensus document established the criteria to evaluate the complexity of seven types of procedures. DRLs were set as the 3rd quartile of KAP values. RESULTS: The KAP (3rd quartile) in Gy cm2 for the procedures included in the survey were: lower extremity arteriography (n = 784) 78; renal arteriography (n = 37) 107; transjugular hepatic biopsies (THB) (n = 30) 45; biliary drainage (BD) (n = 314) 30; uterine fibroid embolization (UFE) (n = 56) 214; colon endoprostheses (CE) (n = 31) 169; hepatic chemoembolization (HC) (n = 269) 303; femoropopliteal revascularization (FR) (n = 62) 119; and iliac stent (n = 66) 170. The complexity involved the increases in the following KAP factors from simple to complex procedures: THB x4; BD x13; UFE x3; CE x3; HC x5; FR x5 and IS x4. CONCLUSIONS: The evaluation of the procedure complexity in patient doses will allow the proper use of DRLs for the optimization of interventional radiology. KEY POINTS: • National DRLs for interventional procedures have been proposed given level of complexity • For clinical audits, the level of complexity should be taken into account. • An evaluation of the complexity levels of the procedure should be made.

The Prevalence, Correlates, Detection and Control of Diabetes among Older People in Low and Middle Income Countries. A 10/66 Dementia Research Group Population-Based Survey.

BACKGROUND: Little is known of the epidemiology of diabetes among older people in low and middle income countries. We aimed to study and compare prevalence, social patterning, correlates, detection, treatment and control of diabetes among older people in Latin America, India, China and Nigeria. METHODS: Cross-sectional surveys in 13 catchment area sites in nine countries. Diagnosed diabetes was assessed in all sites through self-reported diagnosis. Undiagnosed diabetes was assessed in seven Latin American sites through fasting blood samples (glucose > = 7 mmol/L). RESULTS: Total diabetes prevalence in catchment sites in Cuba (prevalence 24.2%, SMR 116), Puerto Rico (43.4%, 197), and urban (27.0%, 125), and rural Mexico (23.7%, 111) already exceeds that in the USA, while that in Venezuela (20.9%, 100) is similar. Diagnosed diabetes prevalence varied very widely, between low prevalences in sites in rural China (0.9%), rural India (6.6%) and Nigeria (6.0%). and 32.1% in Puerto Rico, explained mainly by access to health services. Treatment coverage varied substantially between sites. Diabetes control (40 to 61% of those diagnosed) was modest in the Latin American sites where this was studied. Diabetes was independently associated with less education, but more assets. Hypertension, central obesity and hypertriglyceridaemia, but not hypercholesterolaemia were consistently associated with total diabetes. CONCLUSIONS: Diabetes prevalence is already high in most sites. Identifying undiagnosed cases is essential to quantify population burden, particularly in least developed settings where diagnosis is uncommon. Metabolic risk factors and associated lifestyles may play an important part in aetiology, but this requires confirmation with longitudinal data. Given the high prevalence among older people, more population research is indicated to quantify the impact of diabetes, and to monitor the effect of prevention and health system strengthening on prevalence, treatment and control.

Zinc modulation of basal and ß-adrenergically stimulated L-type Ca2+ current in rat ventricular cardiomyocytes: consequences in cardiac diseases.

Zinc exists in biological systems as bound and histochemically reactive free Zn(2+) in the nanomolar range. Zinc is required as either structural or catalytic component for a large number of enzymes. It also modulates current passage through many ion channels. Here, we reinvestigated the effects of extracellular and intracellular Zn(2+) on the L-type Ca(2+) current (I (CaL)) and its modulation by ß-adrenergic stimulation in rat ventricular cardiomyocytes. In the absence of Ca(2+) ions, Zn(2+) could permeate through the L-type channel at much lower concentrations and at a more positive voltage range, but with a lower permeability than Ca(2+). In the presence of Ca(2+), extracellular Zn(2+) demonstrated strong bimodal inhibitory effects on the I (CaL), with half-inhibition occurring around 30 nM, i.e., in the range of concentrations found in the plasma. Intracellular Zn(2+) also significantly inhibited the I (CaL) with a half-inhibitory effect at 12.7 nM. Moreover, ß-adrenergic stimulation was markedly reduced by intracellular Zn(2+) at even lower concentrations (<1 nM) as a consequence of Zn(2+)-induced inhibition of the adenylyl cyclase. All these effects appeared independent of redox variations and were not affected by dithiothreitol. Thus, both basal intracellular and extracellular Zn(2+) modulate transmembrane Ca(2+) movements and their regulation by ß-adrenergic stimulation. Considering that, in many pathological situations, including diabetes, the extracellular Zn(2+) concentration is reduced and the intracellular one is increased, our results help to explain both Ca(2+) overload and marked reduction in the ß-adrenergic stimulation in these diseases.

From the limits of the classical model of sensitometric curves to a realistic model based on the percolation theory for GafChromic EBT films.

PURPOSE: Modern radiotherapy uses complex treatments that necessitate more complex quality assurance procedures. As a continuous medium, GafChromic EBT films offer suitable features for such verification. However, its sensitometric curve is not fully understood in terms of classical theoretical models. In fact, measured optical densities and those predicted by the classical models differ significantly. This difference increases systematically with wider dose ranges. Thus, achieving the accuracy required for intensity-modulated radiotherapy (IMRT) by classical methods is not possible, plecluding their use. As a result, experimental parametrizations, such as polynomial fits, are replacing phenomenological expressions in modern investigations. This article focuses on identifying new theoretical ways to describe sensitometric curves and on evaluating the quality of fit for experimental data based on four proposed models. METHODS: A whole mathematical formalism starting with a geometrical version of the classical theory is used to develop new expressions for the sensitometric curves. General results from the percolation theory are also used. A flat-bed-scanner-based method was chosen for the film analysis. Different tests were performed, such as consistency of the numeric results for the proposed model and double examination using data from independent researchers. RESULTS: Results show that the percolation-theory-based model provides the best theoretical explanation for the sensitometric behavior of GafChromic films. The different sizes of active centers or monomer crystals of the film are the basis of this model, allowing acquisition of information about the internal structure of the films. Values for the mean size of the active centers were obtained in accordance with technical specifications. In this model, the dynamics of the interaction between the active centers of GafChromic film and radiation is also characterized by means of its interaction cross-section value. CONCLUSIONS: The percolation model fulfills the accuracy requirements for quality-control procedures when large ranges of doses are used and offers a physical explanation for the film response.

[Haemorrhage in arteriovenous malformations of the brain following radiosurgery: the importance of the latency period]. / Hemorragia de las malformaciones arteriovenosas cerebrales tras la radiocirugía: importancia del período de latencia.

INTRODUCTION: Arteriovenous malformations are abnormal communications between arteries and veins. Treatment can consist in surgery, embolisation and/or radiosurgery. AIM: To assess the influence of radiosurgery on the risk of bleeding and related factors. PATIENTS AND METHODS: Retrospective study of 79 patients who were treated with a 6 MV linear accelerator. Clinical, morphological and dosimetric parameters were collected and a statistical analysis was performed to investigate their relationship with bleeding during the latency period. RESULTS: The mean age was 33.7 years, and 56% of patients were females. The mean volume was 6.16 cm(3). Bleeding occurred before treatment in 52.6% of cases. Altogether 25% had been embolised and 7.6% had been treated earlier using radiosurgery. Six patients suffered a haemorrhage after treatment. Bleeding occurred in 21% of those who had undergone embolisation versus 3.6% in non-embolised individuals (p < 0.02). Bleeding occurred in 33.3% of those who had been treated radiosurgically on more than one occasion, and only 5.7% if they were treated just once (p = 0.02). Bleeding took place in 28.6% of lesions above 10 cm(3) and in 3.2% when they were smaller (p < 0.01). Bleeding occurred in 16.1% of patients if they received less than 17 Gy, and in 2.22% if they received 17 or more (p < 0.01). All haemorrhages took place in treatments with more than one isocentre (p < 0.01) and with a higher homogeneity index (p < 0.01). CONCLUSIONS: Radiosurgery does not modify the risk of bleeding. The factors associated to higher percentages of bleeding are also related to poorer closure outcomes and longer latency periods.

Hemorragia de las malformaciones arteriovenosas cerebrales tras la radiocirugía: importancia del período de latencia / Haemorrhage in arteriovenous malformations of the brain following radiosurgery: The importance of the latency period

Introducción. Las malformaciones arteriovenosas son comunicaciones anómalas entre arterias y venas. El tratamiento puede realizarse mediante cirugía, embolización y/o radiocirugía. Objetivo. Evaluar la influencia de la radiocirugíasobre el riesgo de sangrado y los factores relacionados con éste. Pacientes y métodos. Estudio retrospectivo de 79 pacientes tratados con acelerador lineal de 6 MV. Se recogieron parámetros clínicos, morfológicos y dosimétricos, analizando estadísticamentesu relación con el sangrado durante el período de latencia. Resultados. La edad media fue de 33,7 años, y el 56%fueron mujeres. El volumen medio fue de 6,16 cm3. El 52,6% sangró antes del tratamiento. El 25% había sido embolizado y el 7,6% había recibido radiocirugía previamente. Seis pacientes sufrieron hemorragia tras el tratamiento. Sangró el 21% de los embolizados, frente al 3,6% de los no embolizados (p = 0,02). Entre los tratados con más de una radiocirugía sangró el33,3%, y sólo el 5,7% si se trataron una sola vez (p = 0,02). Sangró el 28,6% de las lesiones mayores de 10 cm3 y el 3,2% de las menores (p < 0,01). Sangró el 16,1% si recibieron menos de 17 Gy, y el 2,22% si recibieron 17 o más (p < 0,01). Todas las hemorragias se produjeron en tratamientos con más de un isocentro (p < 0,01) y con índice de homogeneidad más alto (p < 0,01). Conclusiones. La radiocirugía no modifica el riesgo de sangrado. Los factores asociados con mayores porcentajes de hemorragia se relacionan también con peores resultados de cierre y períodos de latencia más prolongados

Introduction. Arteriovenous malformations are abnormal communications between arteries and veins. Treatmentcan consist in surgery, embolisation and/or radiosurgery. Aim. To assess the influence of radiosurgery on the risk of bleeding and related factors. Patients and methods. Retrospective study of 79 patients who were treated with a 6 MV linear accelerator. Clinical, morphological and dosimetric parameters were collected and a statistical analysis was performed to investigate their relationship with bleeding during the latency period. Results. The mean age was 33.7 years, and 56% of patients were females. The mean volume was 6.16 cm3. Bleeding occurred before treatment in 52.6% of cases. Altogether 25% had been embolised and 7.6% had been treated earlier using radiosurgery. Six patients suffered a haemorrhage after treatment. Bleeding occurred in 21% of those who had undergone embolisation versus 3.6% in non-embolised individuals (p < 0.02).Bleeding occurred in 33.3% of those who had been treated radiosurgically on more than one occasion, and only 5.7% if they were treated just once (p = 0.02). Bleeding took place in 28.6% of lesions above 10 cm3 and in 3.2% when they were smaller (p < 0.01). Bleeding occurred in 16.1% of patients if they received less than 17 Gy, and in 2.22% if they received 17 or more (p < 0.01). All haemorrhages took place in treatments with more than one isocentre (p < 0.01) and with a higher homogeneityindex (p < 0.01). Conclusions. Radiosurgery does not modify the risk of bleeding. The factors associated to higher percentagesof bleeding are also related to poorer closure outcomes and longer latency periods

Treatment of occluded distal splenorenal shunts with endovascular stents: a report of two cases.

Surgical treatment of an occluded or stenotic portosystemic shunt is difficult and carries a high risk of mortality. We report two cases of early thrombosis of distal splenorenal shunt (DSRS) successfully treated by transcatheter recanalization and stent placement. At 18-month follow-up, the patients remained asymptomatic and control venograms showed continued patency of the shunt with no evidence of stenosis or collaterals.

Calculation of airborne radioactivity in a Technegas lung ventilation unit.

Airborne contamination by 99Tcm has been monitored in the Nuclear Medicine Department in our hospital to assess the risk of internal contamination to occupational workers exposed to Technegas studies. An air sampler fitted with a membrane filter was used. The optimum time for air absorption for obtaining the maximum activity in the filter was calculated. Maximum activity in the membrane filter ensures minimum uncertainty, which is especially important when low-level activities are being measured. The optimum time depends on air absorption velocity, room volume and filter efficiency for isotope collection. It tends to 1/lambda (lambda = disintegration constant for 99Tcm) for large volume and low velocity. Room activity with the air pump switched on was related to filter activity, and its variation with time was studied. Free activity in air for each study was approximately 7 x 10(-4) the activity used, and the effective half-life of the isotope in the room was 13.9 min (decay and diffusion). For a typical study (630 MBq), the effective dose to staff was 0.01 microSv when in the room for 10 min.

Focal xanthogranulomatous pyelonephritis simulating malignancy in children.

Xantogranulomatous pyelonephritis is a severe chronic form of renal parenquimal infection that usually results in diffuse renal destruction. An unusual case of xanthogranulomatous pyelonephritis in a child is reported which presented as a focal mass without calculus in a functioning kidney and was diagnosed as a renal tumor.

Arteriovenous fistulas in the neck: diagnosis with color Doppler sonography.

We report the use of color Doppler imaging in the diagnosis of four arteriovenous fistulas in the neck region: two had a traumatic origin and two were spontaneous. A perivascular color artifact was the most common initial finding on color images to indicate the underlying abnormality. In all four cases, a low-resistance flow with high systolic and diastolic velocities was observed in the feeding artery. Although angiography remains essential before therapeutic embolization, color Doppler sonography may be an important tool for screening and follow-up of cervical arteriovenous fistulas.

Postnatal development of the occipito-tectal pathway in the rat.

The postnatal development of the occipito-tectal pathway was studied by making single injections of 3H-leucine into the striate cortex of rats ranging in age from newborn to postnatal day 50 (P50). After these injections, the earliest age at which autoradiographic labeling was found in the ipsilateral superior colliculus (SC) was P4. Two main stages were recognized in the development of the occipito-tectal pathway. In the first stage, from P4 to P9, the silver grain pattern over the SC was suggestive of axonal labeling. The label was tangentially and radially exuberant involving the prospective stratum opticum, the adjacent part of the stratum griseum superficiale and also the strata intermediale. A rough topographic order in the projection existed at least from P6. The second stage, from P9 to P17, was characterized by the ingrowth of axonal arbors into the collicular strata superficiale and by the disappearance of the tangentially exuberant projections. Quantitative estimations of the degree of tangential exuberancy of the projection showed that it underwent a reduction of almost 50% from P7 to P17. By P17, the radial and tangential patterns of termination of the occipito-tectal pathway appeared virtually mature. No projections to the contralateral SC were observed at any age. The results of the present study indicate that the mature topographic pattern of the occipito-tectal projection is attained through two separate steps which may involve a number of different mechanisms. In the first step, occipital axons grow orderly -although in an exuberant manner- towards their roughly appropriate tectal locations, remaining to a large extent confined to the collicular white matter. In the second step, further refinement of the topographic map is achieved both by selective growing of terminal arbors into tangentially restricted regions of the tectal surface, and, by retraction of tangentially exuberant projections.