Three-dimensional quantitative evaluation method of nonrigid registration algorithms for adaptive radiotherapy.

PURPOSE: Current radiotherapy is progressing to the concept of adaptive radiotherapy, which implies the adaptation of planning along the treatment course. Nonrigid registration is an essential image processing tool for adaptive radiotherapy and image guided radiotherapy, and the three-dimensional (3D) nature of the current radiotherapy techniques requires a 3D quantification of the registration error that existing evaluation methods do not cover appropriately. The authors present a method for 3D evaluation of nonrigid registration algorithms' performance, based on organ delineations, capable of working with near-spherical volumes even in the presence of concavities. METHODS: The evaluation method is composed by a volume shape description stage, developed using a new ad hoc volume reconstruction algorithm proposed by the authors, and an error quantification stage. The evaluation method is applied to the organ delineations of prostate and seminal vesicles, obtained by an automatic segmentation method over images of prostate cancer patients treated with intensity modulated radiation therapy. RESULTS: The volume reconstruction algorithm proposed has been shown to accurately model complex 3D surfaces by the definition of clusters of control points. The quantification method, inspired by the Haussdorf-Chebysev distance, provides a measure of the largest registration error per control direction, defining a valid metric for concave-convex volumes. Summarizing, the proposed evaluation methodology presents accurate results with a high spatial resolution in a negligible computation time in comparison with the nonrigid registration time. CONCLUSIONS: Experimental results show that the metric selected for quantifying the registration error is of utmost importance in a quantitative evaluation based on measuring distances between volumes. The accuracy of the volume reconstruction algorithm is not so relevant as long as the reconstruction is tight enough on the actual volume of the organ. The new evaluation method provides a smooth and accurate volume reconstruction for both the reference and the registered organ, and a complete 3D description of nonrigid registration algorithms' performance, resulting in a useful tool for study and comparison of registration algorithms for adaptive radiotherapy.

Incidencia y prevalencia de la encefalopatía hipoxico-isquémica en la primera década del siglo XXI / Neonatal hypoxic-ischemic encephalopathy: Incidence and prevalence in the first decade of the 21st century

Objetivos: Examinar la magnitud del problema de la encefalopatía hipoxico-isquémica (EHI) en un hospital terciario en los últimos 9 años, con el fin de valorar la conveniencia y oportunidad de implementar un programa de hipotermia. Métodos: Se identificaron todos los recién nacidos (RN) ≥34 semanas con antecedentes de asfixia intraparto y encefalopatía neonatal, nacidos entre los años 2000 y 2008. La EHI se clasificó como leve, moderada o grave. Se realizó un joinpoint regression analysis para examinar la tendencia en la incidencia de EHI durante el período de estudio y los posibles cambios en ésta. Resultados: Entre el 1 de enero del año 2000 y 31 de diciembre del 2008 nacieron en el Hospital La Paz 90.963 RN vivos, de los cuales 21.228 (23,36%) ingresaron en Neonatología. Otros 200 neonatos ingresaron procedentes de extramuros. Un total de 110 neonatos presentaron EHI, de los cuales 99 (90%) nacieron intramuros. La incidencia global de EHI fue de 1,088 por cada 1.000 RN vivos, y se observó una tendencia decreciente (pendiente = -5,37; p<0,05), y la incidencia de EHI significativa (moderada y grave) fue de 0,49 por cada 1.000. Cincuenta y dos RN tuvieron EHI significativa y hubieran sido candidatos a entrar en un programa de hipotermia; esto supone una prevalencia de 2,42 por cada 1.000 neonatos ingresados y un promedio de 5–6 pacientes/año. Conclusiones: La EHI es un problema infrecuente, particularmente la EHI significativa. La baja prevalencia de esta entidad, aun en centros terciarios, hace necesaria la regionalización y, por tanto, la centralización de los programas de hipotermia, con el fin de garantizar una adecuada calidad asistencial y optimizar los recursos (AU)

Aim: To examine the incidence and the prevalence of neonatal hypoxic-ischemic encephalopathy (HIE) in a tertiary Spanish center over a 9-year period, before the implementation of a hypothermia program. Methods: All infants ≥34 weeks gestation, born between 2000 and 2008 with evidence of perinatal asphyxia and neonatal encephalopathy were identified. HIE was classified as mild, moderate or severe. Joinpoint regression model was used to identify changes in the trends of HIE incidences. Results: A total of 90,963 live infants were born in La Paz Hospital between 2000 and 2008, and 23.3% of them (21.228) were admitted to the Neonatal Unit. In addition, 200 infants were referred from other centers. A total of 110 infants had HIE, of which 90% were inborn. The overall incidence of HIE was 1.088 per 1,000 live births, and the incidence of clinically significant HIE (moderate and severe grades) was 0.49 per 1,000 live births. The incidence of HIE showed a linear downward trend throughout the study period (slope=−5.37; P<0.05). Fifty-two neonates had moderate or severe HIE, this represents a prevalence of 2.42 per 1,000 infants admitted to the Neonatal Unit and means that 5–6 infants a year would have been candidates for therapeutic hypothermia. Conclusions: Neonatal HIE, and in particular significant HIE, is an infrequent condition. The low prevalence of HIE requires that these infants are referred to regional centers with sufficient experience in the use of therapeutic hypothermia, and in the management of all the medical problems associated with HIE (AU)

[Neonatal hypoxic-ischemic encephalopathy: Incidence and prevalence in the first decade of the 21st century]. / Incidencia y prevalencia de la encefalopatía hipoxico-isquémica en la primera década del siglo xxi.

AIM: To examine the incidence and the prevalence of neonatal hypoxic-ischemic encephalopathy (HIE) in a tertiary Spanish center over a 9-year period, before the implementation of a hypothermia program. METHODS: All infants > or =34 weeks gestation, born between 2000 and 2008 with evidence of perinatal asphyxia and neonatal encephalopathy were identified. HIE was classified as mild, moderate or severe. Joinpoint regression model was used to identify changes in the trends of HIE incidences. RESULTS: A total of 90,963 live infants were born in La Paz Hospital between 2000 and 2008, and 23.3% of them (21.228) were admitted to the Neonatal Unit. In addition, 200 infants were referred from other centers. A total of 110 infants had HIE, of which 90% were inborn. The overall incidence of HIE was 1.088 per 1,000 live births, and the incidence of clinically significant HIE (moderate and severe grades) was 0.49 per 1,000 live births. The incidence of HIE showed a linear downward trend throughout the study period (slope=-5.37; P<0.05). Fifty-two neonates had moderate or severe HIE, this represents a prevalence of 2.42 per 1,000 infants admitted to the Neonatal Unit and means that 5-6 infants a year would have been candidates for therapeutic hypothermia. CONCLUSIONS: Neonatal HIE, and in particular significant HIE, is an infrequent condition. The low prevalence of HIE requires that these infants are referred to regional centers with sufficient experience in the use of therapeutic hypothermia, and in the management of all the medical problems associated with HIE.

Cohort study of an outbreak of viral gastroenteritis in a nursing home for elderly, Majorca, Spain, February 2008.

An outbreak of acute gastroenteritis occurred in a nursing home for elderly in Majorca between 4 and 23 February 2008. To know its aetiology and mechanism of transmission a retrospective cohort study was conducted with a fixed cohort including 146 people (96 residents and 50 employees). The data were collected from clinical histories and through a survey by questionnaire. In total 71 cases were identified (53 residents, 18 employees), corresponding to an overall attack rate (AR) of 48.6%.

Tratamiento endoluminal de pseudoaneurisma de aorta torácica tras cirugía abierta de coartación / Edoluminal repair ofthoracic aortic pseudoaneurysm after coarctation open surgery

La formación de un pseudoaneurisma es una de las complicaciones tardías posibles y no infrecuentes de la reparación abierta de las coartaciones de aorta y que comporta una alta morbimortalidad. Presentamos un caso de pseudoaneurisma de aorta torácica con clínica de hemoptisis masiva que fue tratado con éxito mediante la implantación de una endoprótesis aórtica tipo Zenith TX2 (Cook). En la discusión se comentan los diversos factores predictores de la aparición de estos pseudoaneurismas, el seguimiento preciso para diagnosticarlos a tiempo y las posibilidades terapéuticas actuales a la hora de abordar esta grave complicación tardía (AU)

The pseudoaneurysm develop is a late complication of coarctation open repair and bear high morbility and mortality. We show a thoracic aortic pseudoaneurysm case with massive hemoptysis treated with Zenith TX2 (Cook) stent-graft repair. We speak about predictors of this pseudoaneurysm formation, follow up and therapeutic possibilities for approach this problem (AU)

Vesicoureteral reflux: diagnosis and grading with echo-enhanced cystosonography versus voiding cystourethrography.

PURPOSE: To evaluate the usefulness of echo-enhanced cystosonography compared with voiding cystourethrography (VCUG) for detecting and grading vesicoureteral reflux (VUR). MATERIALS AND METHODS: Two hundred sixteen pediatric patients underwent cystosonography enhanced with SH U 508A, a galactose-based echo-enhancing agent. Sonograms of the kidneys and bladder were obtained before filling, during bladder filling, and during voiding. This examination was followed immediately with VCUG. Each kidney or portion of a kidney with its own complete collecting system was considered separately, for a total of 440 kidney units. RESULTS: VUR was detected in 123 kidney units at cystosonography and in 104 at VCUG. In 401 kidney units, there was concordance between results at cystosonography and at VCUG regarding the presence or absence of VUR. Ninety-four kidney units showed VUR with both methods. Seventy-seven of the 94 refluxing units were depicted with the same grade of VUR with both modalities, and in 17 the VUR grade was greater at cystosonography than at VCUG. Twenty-nine of the 94 units showed VUR at only cystosonography, and 10 units at only VCUG. The McNemar test showed that cystosonography depicted a significantly (P = .003) higher number of units with VUR. By patient, VUR was depicted with both studies in 67 and with only one study in 25. VUR was seen at only cystosonography in 16 patients and at only VCUG in nine. The McNemar test for patients showed no significant difference between the two tests in detection of VUR. CONCLUSION: Cystosonography with SH U 508A appears comparable to VCUG in the depiction of VUR.

Postnatal adaptation of brain circulation in preterm infants.

Global and regional postnatal cerebral circulatory changes in stable preterm infants were studied, and their relation to brain injury was assessed. Thirty-five preterm infants were studied on the first and second days of age. Cerebral blood flow (CBF) (mL/hg per min) and cerebral blood volume (CBV) (mL/hg) were measured using near-infrared spectroscopy. The cerebral blood flow velocity (cm/second) (peak systolic, diastolic flow, mean flow) and resistance index (RI) were determined in the internal carotid, anterior cerebral, and striate arteries by color Doppler flow imaging. Serial cerebral ultrasound studies were performed to detect changes in brain parenchymal echogenicity or intraventricular hemorrhage (IVH); the maximum severity of these findings was considered. CBF and cerebral blood flow velocity increased significantly with time, and such changes were independent of mean blood pressure, PO(2), PCO(2), hematocrit, or glycemia. In contrast, CBV and RI remained unchanged. According to the results of sonograms, no differences were found in postnatal CBF and cerebral blood flow velocity changes, regardless of whether patients had or did not have parenchymal lesions or IVH. However, higher CBV values were found on the second day in infants with IVH compared with infants without IVH. Early coupling of CBF and metabolic demands is independent of blood pressure. Improved venous return, instead of vasodilation, could be important in this adaptation.

Anomalías congénitas de la uretra: diagnóstico radiológico / Congenital anomalies of the uretra: radiological diagnosis

Este artículo revisa una serie de anomalías congénitas frecuentes e infrecuentes que afectan a la uretra, e ilustra la utilidad de la urografía, cistografía miccional y ecografía en el diagnóstico y manejo de estas alteraciones. Las anomalías de la uretra incluyen válvulas de uretra posterior, duplicación uretral, divertículos uretrales, megalouretra y fístula uretral. Se incluye, así mismo, la malformación de la cloaca y el seno urogenital. Las bases embriológicas y patológicas de las diferentes patologías se discuten en cada apartado (AU)

Anomalías congénitas del uréter y de la vejiga: diagnóstico radiológico / Congenital anomalies of the ureter and the bladder: radiological diagnosis

La evaluación de los pacientes con anomalías congénitas del tracto urinario inferior requiere frecuentemente múltiples modalidades de imagen para el diagnóstico y el planteamiento de la corrección quirúrgica. Este artículo revisa una serie de anomalías congénitas frecuentes e infrecuentes que afectan al uréter dista¡ y a la vejiga, e ilustra la eficacia de las placas simples, urografía, cistografía miccional y ecografía en el diagnóstico y manejo de estas alteraciones. Las anomalías del uréter distal incluyen ureteroceles simples, ureteroceles ectópicos y uréteres ectápicos en múltiples localizaciones. En las anomalías vesicales incluimos divertículos, duplicación vesical tanto en el plano frontal como sagital y anomalías del uraco tales como persistencia del uraco, quiste uracal y divertículo uracal. Las bases embriológicas y patológicas de los diferentes hallazgos radiográficos se discuten en los casos apropiados (AU)

Cerebral haemodynamics in preterm infants after exposure to dexamethasone.

AIM: To determine changes in brain haemodynamics produced by dexamethasone; to evaluate the pathophysiological conditions involved in the effect of dexamethasone. METHODS: A prospective study was made of 12 ventilated preterm infants who received dexamethasone (0.25 mg/kg/12 hours) for ongoing chronic lung disease or extubation failure. Cerebral blood flow (CBF), absolute cerebral blood volume (CBV), and cerebral blood volume changes (delta CBV) were estimated by near infrared spectroscopy, before and 10, 30, 60, 120, 180 and 240 minutes after the first, third, and fifth doses of dexamethasone. All patients were monitored continuously using pulse oximetry, transcutaneous blood gases, and blood pressure. RESULTS: There were significant short term changes in delta CBV on each day of the study; delta CBV increased significantly at 240 minutes compared with values before the first dose, and from 120 minutes onward during the third and fifth doses. However, mean CBV values averaged over 240 minutes after the first, third, and fifth doses did not vary. Mean CBF values averaged over 240 minutes increased progressively up to the fifth dose (significant differences between the first and fifth dose). The short term changes in CBF consisted of a significant increase 60 minutes after dexamethasone administration compared with the before and 10 minute values in every study. Blood pressure was significantly higher in the third and fifth doses than in the first dose. Blood pressure showed no short term changes. There was no correlation between CBF and blood pressure changes. TcPCO2 (transcutaneous PCO2) decreased significantly throughout the study period, with the average mean value in the fifth dose significantly lower than in the first dose. Nevertheless, no short term changes in TcPCO2 were observed. CONCLUSIONS: Postnatal systemic dexamethasone administration produced significant changes in cerebral haemodynamics that seemed to be related to both a direct effect on regional vessel walls and the cumulative effect of dexamethasone.

Multiple organ involvement in perinatal asphyxia.

OBJECTIVES: (1) To evaluate the frequency and spectrum of severity of multisystem dysfunction after perinatal asphyxia and (2) to analyze the relationship between the clinical and biochemical markers of perinatal asphyxia and multiorgan involvement. STUDY DESIGN: Seventy-two consecutive term newborn infants with perinatal asphyxia were studied prospectively. Systematic neurologic, renal, pulmonary, cardiac, and gastrointestinal evaluations were performed. Involvement of each organ was classified as moderate or severe. RESULTS: Involvement of one or more organs occurred in 82% of the infants; the central nervous system (CNS) was most frequently involved (72%). Severe CNS injury (7 infants) always occurred with involvement of other organs, although moderate CNS involvement was isolated in 14 infants. Renal involvement occurred in 42%, pulmonary in 26%, cardiac in 29%, and gastrointestinal in 29% of the infants; 15% neonates had renal failure and 19% had respiratory failure. The Apgar scores at 1 and 5 minutes were the only perinatal factors related to the number of organs involved and the severity of involvement; the Apgar score at 5 minutes had the stronger independent association. No relationship or organ dysfunction was found with the umbilical cord arterial blood pH, meconium-stained amniotic fluid, umbilical cord abnormalities, presentation, or type of delivery. CONCLUSIONS: Our findings indicate that the Apgar score at 5 minutes, in infants who have other criteria for asphyxia, is the perinatal marker that may best identify infants at risk of organ dysfunction.

Value of clinical analysis in epidemiological research: the Spanish registry experience.

Using data from the Spanish Collaborative Study of Congenital Malformations (ECEMC), a hospital-based, case-control study and surveillance program, we investigated the potential value of registry systems in the identification of causes of congenital defects when their methodology includes (1) detailed reporting and coding of all anomalies present in each child, whether major or minor, (2) clinical analysis and coding of the global pattern of anomalies present in each infant, and (3) classification of all children studied according to their clinical presentation. These approaches provide great specificity and flexibility in the retrieval and analysis of data. Not only do they permit the study of specific anomalies, but also the analysis of children with MCA patterns, as well as the study of the relationship of specific defects with the rest of the anomalies present in a child. To illustrate this point, we present general data on 15,307 malformed children and more specific information on 153 cases of anal atresia/stenosis identified among the 753,410 live-births surveyed by the ECEMC between April 1976 and September 1989.