Metodología de la gammagrafía con leucocitos marcados en el diagnóstico de infección osteoarticular protésica/no protésica: ¿análisis visual o semicuantitativo? ¿Protocolo de uno o 2 días? / Diagnostic methodology in labelled leukocyte scan for prosthetic / non-prosthetic osteoarticular infection: Visual or semi-quantitative analysis? One- or two-day protocol?

Objetivo: Como hay poca literatura sobre el tema, nos propusimos comparar la utilidad diagnóstica del análisis semicuantitativo versus el análisis visual en la escintigrafía de glóbulos blancos etiquetados (WBCS) para la infección osteoarticular. Se evaluaron protocolos de uno y dos días, en particular en los dispositivos ortopédicos.Material y métodos: Estudio prospectivo de 79 pacientes consecutivos con sospecha de infección osteoarticular. En todos los pacientes, la SCBM se realizó a los 30 min, 4 h, 8 h y 24 h. Las imágenes se analizaron agrupándolas en dos protocolos: protocolo de un día (los expertos evaluaron imágenes planas de 30 min, 4 h y 8 h) y protocolo de dos días (los expertos evaluaron imágenes planas de 30 min, 4 h y 24 h). Las imágenes planas se interpretaron cualitativa y semicuantitativamente y también se compararon agrupando a los pacientes con y sin dispositivos ortopédicos. Para determinar qué valor de corte de la variación porcentual podía predecir la infección osteoarticular, se calcularon múltiples valores de corte en ambos protocolos a partir del índice de Youden. Tres lectores ciegos analizaron las imágenes.Resultados: Comparando el diagnóstico final, el análisis visual del protocolo de un día proporcionó mejores resultados con una sensibilidad del 95,5%, una especificidad del 93% y una precisión diagnóstica del 93,7% (p < 0,01) que el protocolo de dos días con valores del 86,4%, 94,7% y 92,4%, respectivamente (p < 0,01). Para el análisis semicuantitativo, el protocolo de un día también obtuvo mejores resultados con una sensibilidad del 72,7%, una especificidad del 78,9% y una precisión del 77,2% (p < 0,01) que el protocolo de dos días (sin resultados significativos; p = 0,14), especialmente en el grupo de pacientes con aparatos ortopédicos (sensibilidad del 100%, especificidad del 79,5% y precisión del 82,7%; p < 0,01)

Objective: As scarce literature on the topic is available, we aimed to compare diagnostic utility of semi-quantitative versus visual analysis in labelled white blood cell scintigraphy (WBCS) for osteoarticular infection. One-day and two-day protocols were assessed, particularly in orthopaedic devices.Material and methods: Prospective study of 79 consecutive patients with suspected osteoarticular infection. In all patients, WBCS were performed at 30min, 4h, 8h and 24h. Images were analysed by grouping in two protocols: one-day-protocol (experts evaluated 30min, 4h and 8h planar images) and two-day-protocol (experts evaluated 30min, 4h and 24h planar images). Planar images were interpreted qualitative and semiquantitatively and also were compared grouping patients with and without orthopaedic devices. To find which cut-off value of the percentage variation could predict of osteoarticular infection, multiple cut-off values were calculated in both protocols from the Youden index. Three blinded readers analysed the images.Results: Comparing final diagnosis visual analysis of the one-day-protocol provided better results with sensitivity of 95.5%, specificity of 93% and diagnostic accuracy of 93.7% (P<.01) than the two-day-protocol with values of 86.4%, 94.7% and 92.4%, respectively (P<.01). For semi-quantitative analysis, the one-day-protocol also obtained better results with sensitivity of 72.7%, specificity of 78.9% and accuracy of 77.2% (P<.01) than two-day-protocol (no significant results; P=.14), especially in the group of patients with orthopaedic devices (sensitivity of 100%, specificity of 79.5% and accuracy of 82.7%; P<.01).Conclusions: Most accurate approach in the diagnosis of osteoarticular infection corresponded to visual analysis in one-day-protocol that showed greater sensitivity and specificity than semi-quantitative analysis. Semi-quantitative analysis only could be useful when visual analysis is doubtful

Diagnostic methodology in labelled leukocyte scan for prosthetic / non-prosthetic osteoarticular infection: Visual or semi-quantitative analysis? One- or two-day protocol? / Metodología de la gammagrafía con leucocitos marcados en el diagnóstico de infección osteoarticular protésica/no protésica: ¿análisis visual o semicuantitativo? ¿Protocolo de uno o 2 días?

OBJECTIVE: As scarce literature on the topic is available, we aimed to compare diagnostic utility of semi-quantitative versus visual analysis in labelled white blood cell scintigraphy (WBCS) for osteoarticular infection. One-day and two-day protocols were assessed, particularly in orthopaedic devices. MATERIAL AND METHODS: Prospective study of 79 consecutive patients with suspected osteoarticular infection. In all patients, WBCS were performed at 30min, 4h, 8h and 24h. Images were analysed by grouping in two protocols: one-day-protocol (experts evaluated 30min, 4h and 8h planar images) and two-day-protocol (experts evaluated 30min, 4h and 24h planar images). Planar images were interpreted qualitative and semiquantitatively and also were compared grouping patients with and without orthopaedic devices. To find which cut-off value of the percentage variation could predict of osteoarticular infection, multiple cut-off values were calculated in both protocols from the Youden index. Three blinded readers analysed the images. RESULTS: Comparing final diagnosis visual analysis of the one-day-protocol provided better results with sensitivity of 95.5%, specificity of 93% and diagnostic accuracy of 93.7% (P<.01) than the two-day-protocol with values of 86.4%, 94.7% and 92.4%, respectively (P<.01). For semi-quantitative analysis, the one-day-protocol also obtained better results with sensitivity of 72.7%, specificity of 78.9% and accuracy of 77.2% (P<.01) than two-day-protocol (no significant results; P=.14), especially in the group of patients with orthopaedic devices (sensitivity of 100%, specificity of 79.5% and accuracy of 82.7%; P<.01). CONCLUSIONS: Most accurate approach in the diagnosis of osteoarticular infection corresponded to visual analysis in one-day-protocol that showed greater sensitivity and specificity than semi-quantitative analysis. Semi-quantitative analysis only could be useful when visual analysis is doubtful. In patients with joint prostheses, an increase in percentage variation above 9% obtained maximum sensitivity and negative predictive value.

Evaluación mediante mapas estadísticos paramétricos de los cambios de la perfusión cerebral en pacientes con estenosis de la arteria carótida sometidos a endarterectomía / Evaluation by “statistical parametric mapping” of the cerebral perfusion changes in patients with carotid artery stenosis after endarterectomy

La eficacia de la endarterectomía carotídea (EC) en los accidentes cerebrovasculares producidos por estenosis carotídea puede ser evaluada mediante la tomografía computarizada de emisión de fotón único de perfusión cerebral, utilizando SPM (statistical parametric mapping ‘mapas estadísticos paramétricos’).Material y métodosSe incluyeron en el estudio 12 pacientes con estenosis significativa de la arteria carótida que fueron sometidos a endarterectomía. A todos se les realizó un estudio de perfusión cerebral con 99mTc-etilen cisteinato dietilester (ECD) basal tras la endarterectomía. Mediante los SPM se comparó de forma independiente el estudio basal/poscirugía con el grupo control formado por 20 pacientes y se obtuvieron los correspondientes SPM. Se valoraron los cambios tanto en extensión (o número de vóxeles) como en intensidad (cambio en el valor de T) de las zonas significativamente hipoperfundidas y el sentido de estos cambios.ResultadosEn el grupo de 12 pacientes se observó una mejoría de la perfusión cerebral posquirúrgica, en 5 pacientes con disminución en la extensión de las zonas hipoperfundidas del 50,56% y de intensidad del 30,9% de media. Cuatro pacientes mostraron un aumento en la extensión de la hipoperfusión cerebral del 85,53% y de la intensidad del 34,21% de media. En tres pacientes no se apreciaron cambios significativos entre ambos estudios.ConclusionesEl SPM ha demostrado ser una herramienta útil que permite objetivar los cambios de flujo sanguíneo cerebral que se producen tras la intervención quirúrgica, valorando los cambios en extensión e intensidad de las zonas significativamente hipoperfundidas(AU)

The efficacy of carotid endartectomy (CE) in cerebrovascular accidents produced by carotid stenosis can be evaluated with the cerebral perfusion with single photon emission tomography, using statistical parametric mapping (SPM).Material and methodsTwelve patients with significant carotid stenosis who underwent endartectomy were included in the study. All underwent a cerebral perfusion study with 99mTc-etilen cisteinato dietilester (ECD) at baseline and after the endartectomy. Using SPM, the baseline/post-surgery study was compared independently with the control group made up of 20 patients and the corresponding parametric statistical mappings were obtained. Changes in extension (kE or voxel number) and intensity (change in the T value) of the significantly hypoperfused zones and direction of these changes were evaluated.ResultsIn the group of 12 patients, improvement of the post-surgical cerebral perfusion was observed in 5 patients with an average 50.56% decrease in the extension of the hypoperfused zones and average 30.9% decrease of intensity. Four patients showed an average 85.53% increase in the extension of cerebral hypoperfusion and of 34.21% in intensity. No significant changes between both studies were found in three patients.ConclusionsSPM has been shown to be a useful tool that makes it possible to objectify the cerebral brain flow changes produced after the surgical intervention, evaluating the changes in extension and intensity of the significantly hypoperfused zones(AU)

[Evaluation by "statistical parametric mapping" of the cerebral perfusion changes in patients with carotid artery stenosis after endarterectomy]. / Evaluación mediante mapas estadísticos paramétricos de los cambios de la perfusión cerebral en pacientes con estenosis de la arteria carótida sometidos a endarterectomía.

UNLABELLED: The efficacy of carotid endartectomy (CE) in cerebrovascular accidents produced by carotid stenosis can be evaluated with the cerebral perfusion with single photon emission tomography, using statistical parametric mapping (SPM). MATERIAL AND METHODS: Twelve patients with significant carotid stenosis who underwent endartectomy were included in the study. All underwent a cerebral perfusion study with 99mTc-etilen cisteinato dietilester (ECD) at baseline and after the endartectomy. Using SPM, the baseline/post-surgery study was compared independently with the control group made up of 20 patients and the corresponding parametric statistical mappings were obtained. Changes in extension (k(E) or voxel number) and intensity (change in the T value) of the significantly hypoperfused zones and direction of these changes were evaluated. RESULTS: In the group of 12 patients, improvement of the post-surgical cerebral perfusion was observed in 5 patients with an average 50.56% decrease in the extension of the hypoperfused zones and average 30.9% decrease of intensity. Four patients showed an average 85.53% increase in the extension of cerebral hypoperfusion and of 34.21% in intensity. No significant changes between both studies were found in three patients. CONCLUSIONS: SPM has been shown to be a useful tool that makes it possible to objectify the cerebral brain flow changes produced after the surgical intervention, evaluating the changes in extension and intensity of the significantly hypoperfused zones.

[Calculation of the left ventricular ejection fraction. Comparison between 4 different instruments]. / Determinación de la fracción de eyección del ventrículo izquierdo realizada con 4 programas de cálculo distintos.

AIM: The aim of this study was to analyse the relationship between left ventricular ejection fractions (EF) obtained using four different instruments. MATERIAL AND METHODS: Eighty-five EF values were analysed. Gated acquisition was performed with the same gammacamera (SOPHA) using 99mTc-labelled red cells. Each EF was obtained using four processing systems: NXT (SOPHA), Entegra (Gems), Odyssey (Philips) and Esoft (Siemens), always working in automated mode. The paired student's t-test, Spearman correlation and Bland-Altman analysis were used to compare methods, and Deming regression was applied. RESULTS: Mean values and standard deviations for each program were: NXT: 61 +/- 9; Entegra: 60 +/- 10; Odyssey: 60 +/- 9; Esoft: 60 +/- 10. Although no significant differences were found as a whole and the values were linearly related, the methods are not interchangeable. CONCLUSIONS: The same program should be used in the follow-up of each patient, which is now easily achievable by means of the DICOM standard.

Determinación de la fracción de eyección del ventrículo izquierdo realizada con 4 programas de cálculo distintos / Calculation of the left ventricular ejection fraction. Comparison between 4 different instruments

Objetivo. Analizar la relación existente entre los valores de la fracción de eyección (FE) del ventrículo izquierdo obtenidos mediante ventriculografía isotópica en equilibrio utilizando cuatro equipos de procesado distintos. Material y métodos. Se han estudiado 85 FE. Las adquisiciones se realizaron en una única gammacámara (Sopha®) mediante sincronización con el electrocardiograma (ECG) y utilizando hematíes marcados con Tc-99m. Se ha obtenido cada una de las FE por cuatro sistemas de procesado: NXT (Sopha®), Entegra (Gems®), Odissey (Philips®) y Esoft (Siemens®). El modo empleado por defecto era el de cálculo automático. Se aplicó la prueba de comparación de medias para datos apareados agrupando las 4 series de datos dos a dos. Asimismo, se buscó la correlación de Spearman y se aplicó la prueba de Bland-Altman para intercambiabilidad y se analizó su regresión por el método de Deming. Resultados. Los valores medios ± desviación estándar según cada programa fueron: NXT: 61 ± 9, Entegra: 60 ± 10, Odyssey: 60 ± 9, Esoft: 60 ± 10. No se han detectado globalmente diferencias, pero los 4 programas generan valores no intercambiables entre sí. Conclusiones. Aunque linealmente relacionados y sin diferencias significativas, se concluye que si se han de comparar estudios de un mismo paciente se emplee el mismo programa, cosa actualmente factible mediante el formato DICOM

Aim. The aim of this study was to analyse therelationship between left ventricular ejection fractions (EF) obtained using four different instruments.Material and methods. Eighty-five EF values were analysed. Gated acquisition was performed with the same gammacamera (SOPHA®) using 99mTc-labelled red cells. Each EF was obtained using four processing systems: NXT (SOPHA®), Entegra (Gems®), Odyssey (Philips®) and Esoft (Siemens®), always working in automated mode.The paired student’s t-test, Spearman correlation andBland-Altman analysis were used to compare methods,and Deming regression was applied. Results. Mean values and standard deviations for each program were: NXT: 61 ± 9; Entegra: 60 ± 10; Odyssey: 60 ± 9; Esoft: 60 ± 10.Although no significant differences were found as a wholeand the values were linearly related, the methods are not interchangeable. Conclusions. The same program should be used in the follow- up of each patient, which is now easily achievable by means of the DICOM standard (AU)

[Lymphoscintigraphy and sentinel node biopsy in non-palpable breast cancer]. / Linfogammagrafía y biopsia del ganglio centinela en el carcinoma no palpable de mama.

OBJECTIVE: The aim of the study was to evaluate the efficacy of lymphatic mapping and sentinel node biopsy in non-palpable breast cancer (NPBC) patients in comparison with palpable breast cancer (PBC) patients. MATERIAL AND METHODS: 199 breast cancer patients were studied. Patients were classified into two groups: NPBC and PBC. Following sentinel node biopsy all patients underwent axillary lymphadenectomy. Surgery was performed at 4-24 h after peritumoral injection of 111MBq 99mTc-nanocolloid. Histological sentinel node analysis was performed by cytological imprinting and delayed study. The following parameters were analyzed in both groups: scintigraphic and surgical detection rates, true positives (TP), true negatives (TN), sensitivity (S), predictive negative value (PNV), false negative rate (FNR) and global precision (GP) of the technique. RESULTS: No significant differences were observed (p > 0.05) in either the lymphoscintigraphy or surgical sentinel node detection, or drainage to internal mammary chain (p = 0.211) in both groups. Metastatic axillary prevalence was lower in NPBC group (p = 0.019). Similar S, NPV and GP values (>90 %) and FNR (< or = 6 %) were found in both groups. CONCLUSIONS: The reliability of the technique is similar in both groups. Drainage is predominantly axilar. Drainage to internal mammary chain was more frequently seen in medial tumours and in NPBC. Metastatic axillary prevalence was lower in the NPBC group.

[Influence of radioactive concentration and storage time on radiochemical purity of 18F-FDG]. / Influencia de la concentración radiactiva y el tiempo de almacenamiento sobre la pureza radioquímica de la 2-[18F]-fluoro-2-desoxi-D-glucosa.

OBJECTIVE: To study the influence of the 18F-FDG radioactive concentration and the usual greatest storage time of the radiopharmaceutical at the Radiopharmacy Unit (RU) over its radiochemical purity. MATERIAL AND METHODS: Thirty 18F-FDG preparations coming from different batches were studied. The radiochemical purity was determined at the RU by means of TLC to saline-diluted (1:10) and undiluted samples of each preparation, in the early 30 minutes since its arrival and 5 hours later. The radiochemical purity of the original 18F-FDG was determined at the PET radiopharmaceutical producer Laboratory (PETL) by means of HPLC in the early hour since the 18F-FDG dispensing. RESULTS: The increase of 18F-Fluoride found in the (5 h-30 min) period was significantly greater in the samples without diluting than in the diluted ones (p < 0.0001). We found a significant correlation between the percent of this increase of 18F-Fluoride (y) and the radioactive concentration of the 18F-FDG (x): y = 0.00061x + 0.1759 (R2 = 0.198; p < 0.0005). The percent of 18F-Fluoride determined at the RU was significantly higher than the percent of 18F-Fluoride determined at the PETL (p < 0.0001). A significant correlation between the differences of the percent of 18F-Fluoride determined by TLC and HPLC (y) and the radioactive concentration (x) was found: y = 0.0139x + 0.3146 (R2 = 0.196; p = 0.016). A significant correlation among the differences of percent 18F-Fluoride determined by TLC and HPLC ([%F] RU - [%F] PETL), the radioactive concentration (RC) and the time since the radiopharmaceutical dispensing (t) was found: [%F] RU - [%F] PETL = 0.01159*RC (mCi/mL) + 0.250*t (h) - 0.01903 (R2 = 0.226; p < 0.014). CONCLUSIONS: The stability of the 18F-FDG preparations with time increases when diminishing its concentration. We recommended the dilution of these preparations with physiological saline solution.

Influencia de la concentración radiactiva y el tiempo de almacenamiento sobre la pureza radioquímica de la 2- (18F) -fluoro-2-desoxi-D-glucosa / Influence of radioactive concentration and storage time on radiochemical purity of 18F-FDG

Objetivo. Determinar la influencia de la concentración radiactiva de la 2-[ 18F]-fluoro-2-desoxi-D-glucosa ( 18F-FDG) y el tiempo de almacenamiento máximo habitual del radiofármaco en la Unidad de Radiofarmacia (UR) sobre su pureza radioquímica. Material y métodos. Se estudiaron 30 preparaciones de 18F-FDG procedentes de lotes diferentes. Se determinó la pureza radioquímica en la UR dentro de los 30 minutos siguientes a su recepción y a las 5 horas mediante cromatografía en capa fina (TLC) a las muestras diluidas con suero salino fisiológico (1:10) y sin diluir. La pureza radioquímica también se determinó en el Laboratorio de radiofármacos PET (LPET) dentro de la primera hora posterior a su dispensación por cromatografía líquida a alta presión (HPLC). Resultados. El aumento de porcentaje de 18F-Fluoruro a las 5 horas fue significativamente mayor en las muestras sin diluir que en las diluidas (p < 0,0001), encontrándose una correlación significativa entre el aumento de porcentaje de 18F-Fluoruro con el tiempo (y) respecto a la concentración radiactiva (x): y = 0,0061x + 0,1759 (R 2 = 0,1977; p < 0,0005). El porcentaje de 18F-Fluoruro determinado en la UR fue significativamente mayor que el determinado en el LPET (p < 0,0001), obteniéndose una correlación significativa entre el aumento de porcentaje de 18F-Fluoruro (y) y la concentración radiactiva (x): y = 0,0139x + 0,3146 (R 2 = 0,196; p = 0,016). Se obtuvo una correlación significativa entre este aumento ([ %F] UR ­ [ %F] LPET), la concentración radiactiva (CR) y el tiempo desde la dispensación (t): [ %F] UR ­ [ %F] LPET = 0,01159*CR (mCi/ml) + 0,250*t (h) ­ 0,01903 (R 2 = 0,226; p = 0,014). Conclusiones. La estabilidad de las preparaciones de 18F-FDG aumenta al disminuir su concentración. Aconsejamos la dilución de estas preparaciones con solución salina fisiológica

Objective. To study the influence of the 18F-FDG radioactive concentration and the usual greatest storage time of the radiopharmaceutical at the Radiopharmacy Unit (RU) over its radiochemical purity. Material and methods. Thirty 18F-FDG preparations coming from different batches were studied. The radiochemical purity was determined at the RU by means of TLC to saline-diluted (1:10) and undiluted samples of each preparation, in the early 30 minutes since its arrival and 5 hours later. The radiochemical purity of the original 18F-FDG was determined at the PET radiopharmaceutical producer Laboratory (PETL) by means of HPLC in the early hour since the 18F-FDG dispensing. Results. The increase of 18F-Fluoride found in the (5 h-30 min) period was significantly greater in the samples without diluting than in the diluted ones (p < 0,0001). We found a significant correlation between the percent of this increase of 18F-Fluoride (y) and the radioactive concentration of the 18F-FDG (x): y = 0,00061x + 0,1759 (R 2 = 0,198; p < 0,0005). The percent of 18F-Fluoride determined at the RU was significantly higher than the percent of 18F-Fluoride determined at the PETL (p < 0,0001). A significant correlation between the differences of the percent of 18F-Fluoride determined by TLC and HPLC (y) and the radioactive concentration (x) was found: y = 0,0139x + 0,3146 (R 2 = 0,196; p = 0,016). A significant correlation among the differences of percent 18F-Fluoride determined by TLC and HPLC ([ %F] RU ­ [ %F] PETL), the radioactive concentration (RC) and the time since the radiopharmaceutical dispensing (t) was found: [ %F] RU ­ [ %F] PETL = 0,01159*RC (mCi/mL) + 0,250*t (h) ­ 0,01903 (R 2 = 0,226; p < 0,014). Conclusions. The stability of the 18F-FDG preparations with time increases when diminishing its concentration. We recommended the dilution of these preparations with physiological saline solution