Patterns of 11C-PIB cerebral retention in mild cognitive impairment patients / Patrones de retención cerebral de 11C-PIB en pacientes con deterioro cognitivo leve

Objective. To evaluate the patterns of cerebral cortical distribution of 11C-PIB in patients with mild cognitive impairment (MCI). Material and methods. The study included 69 patients (37 male, age range 42-79 years) with MCI, sub-classified as 53 with amnestic-MCI (A-MCI), and 16 with non-amnestic-MCI (NA-MCI). Patients underwent 11C-PIB PET/CT scan 60 min after intravenous injection of the radiotracer. A visual analysis of the images was performed by 2 experienced physicians. 11C-PIB-positive studies were considered when gray matter uptake was equal to or greater than white matter. According to the regions involved, 11C-PIB-positive studies were classified into A-pattern (predominant retention in frontal, anterior cingulate, lateral temporal, and basal ganglia) and B-pattern (generalized retention). Results. Thirty-nine of the 69 (56%) patients with MCI showed 11C-PIB retention. Of the 53 A-MCI patients, 36 (68%) showed 11C-PIB retention. Eleven out of 36 (30%) positive scans in A-MCI patients showed A-pattern, and 25 out of 36 (70%) patients had a B-pattern. Positive 11C-PIB was observed in 3 out of 16 (19%) patients with NA-MCI. Regional distribution in these 3 patients showed A-pattern in 1, and B-pattern in 2 patients. Conclusion. Cortical retention of 11C-PIB was more frequent in A-MCI than in NA-MCI patients, and also B-pattern than A-pattern in the 11C-PIB positive group. The recognition of 11C-PIB distribution patterns allows MCI patients to be classified, and the A-pattern may offer a therapeutic window for potential future treatments (AU)

Objetivo. Evaluar los patrones de distribución cortical cerebral de 11C-PIB en pacientes con deterioro cognitivo leve (DCL). Material y métodos. El estudio incluyó 69 pacientes (37 varones, rango de edad 42-79 años) con DCL, que fueron clasificados en 53 DCL amnésico (DCL-A) y 16 DCL no amnésico (DCL-NA). Se obtuvo una PET/TC 11C-PIB 60 min después de la inyección intravenosa del radiotrazador. Se realizó un análisis visual de las imágenes por 2 médicos con experiencia. Los estudios 11C-PIB se consideraron positivos cuando la captación en la sustancia gris fue igual o superior a la captación en la sustancia blanca. Dependiendo de las regiones afectadas, los estudios 11C-PIB positivos se clasificaron en patrón A (retención predominante en frontal, cingulado anterior, lateral temporal y ganglios basales) y patrón B (retención generalizada). Resultados. De los 69 pacientes con DCL, 39 (56%) mostraron retención de 11C-PIB. De los 53 pacientes DCL-A, 36 (68%) tuvieron retención cerebral de 11C-PIB. Once de los 36 (30%) estudios positivos en los pacientes DCL-A mostraron un patrón A y 25 de los 36 (70%) pacientes presentaron un patrón B. Se observaron estudios 11C-PIB positivos en 3 de los 16 (19%) pacientes con DCL-NA. En estos 3 pacientes la distribución regional mostró patrón A en uno y patrón B en 2 pacientes. Conclusión. La retención cortical de 11C-PIB fue más frecuente en pacientes con DCL-A que en pacientes con DCL-NA, y, asimismo, el patrón B que el patrón A en el grupo 11C-PIB positivo. La identificación de los patrones de distribución de 11C-PIB permite una caracterización de los pacientes con DCL; el patrón A puede ofrecer una ventana para potenciales tratamientos en el futuro (AU)

Patterns of 11C-PIB cerebral retention in mild cognitive impairment patients.

OBJECTIVE: To evaluate the patterns of cerebral cortical distribution of (11)C-PIB in patients with mild cognitive impairment (MCI). MATERIAL AND METHODS: The study included 69 patients (37 male, age range 42-79 years) with MCI, sub-classified as 53 with amnestic-MCI (A-MCI), and 16 with non-amnestic-MCI (NA-MCI). Patients underwent (11)C-PIB PET/CT scan 60min after intravenous injection of the radiotracer. A visual analysis of the images was performed by 2 experienced physicians. (11)C-PIB-positive studies were considered when gray matter uptake was equal to or greater than white matter. According to the regions involved, (11)C-PIB-positive studies were classified into A-pattern (predominant retention in frontal, anterior cingulate, lateral temporal, and basal ganglia) and B-pattern (generalized retention). RESULTS: Thirty-nine of the 69 (56%) patients with MCI showed (11)C-PIB retention. Of the 53 A-MCI patients, 36 (68%) showed (11)C-PIB retention. Eleven out of 36 (30%) positive scans in A-MCI patients showed A-pattern, and 25 out of 36 (70%) patients had a B-pattern. Positive (11)C-PIB was observed in 3 out of 16 (19%) patients with NA-MCI. Regional distribution in these 3 patients showed A-pattern in 1, and B-pattern in 2 patients. CONCLUSION: Cortical retention of (11)C-PIB was more frequent in A-MCI than in NA-MCI patients, and also B-pattern than A-pattern in the (11)C-PIB positive group. The recognition of (11)C-PIB distribution patterns allows MCI patients to be classified, and the A-pattern may offer a therapeutic window for potential future treatments.

18F-FDG PET/CT for the detection of large vessel vasculitis in patients with polymyalgia rheumatica / 18F-FDG PET/TAC en pacientes con polimialgia reumática y sospecha de vasculitis de grandes vasos asociada

Purpose: Polymyalgia rheumatica (PMR) may present together with large vessel vasculitis (LVV), and frequently requires a more intensive therapy. The aim of the study was to evaluate the impact of 18F-FDG PET/CT in the diagnosis and management of LVV associated to PMR. Material and methods: This prospective study included 40 consecutive patients (27 women/13 men, 68.10±10.27 years) with PMR and suspicion of associated LVV submitted for 18F-FDG PET/CT. A PET/CT scan was obtained 180min after 18F-FDG intravenous injection. A visual analysis was performed on the images. Five vascular regions were evaluated: supra-aortic trunks (SAT), thoracic aorta (TA), abdominal aorta (AA), iliac arteries (IA), and femoral/tibioperoneal arteries (FTA). The intensity of uptake was graded from 0 to 3. A final diagnosis of LVV was established in 26/40 patients (65%). Results: In the 26 patients with a diagnosis of LVV, the highest intensity of 18F-FDG uptake was observed in the TA, SAT, and FTA. All of these patients showed uptake at the TA, with grade 2 and 3 in most cases. In 4 of the 14 patients without LVV, no uptake was observed in any vascular region, and in the other 10 patients only a grade 1 uptake was observed in 1 or to 2 territories. Out of the 20 treated LVV patients, 18F-FDG PET/CT led to a therapeutic change in 17 (85%). Conclusion: 18F-FDG PET/CT was useful in identifying patients with LVV associated to PMR. The detection of vascular inflammation had an important impact, and led to a change of treatment in a high percentage of patients with LVV

Objetivo: La polimialgia reumática (PMR) puede presentarse asociada a vasculitis de grandes vasos (VGV), necesitando frecuentemente una intensificación del tratamiento. Nuestro objetivo fue evaluar el impacto de la 18F-FDG PET/TAC en el diagnóstico y tratamiento de VGV asociada a PMR. Material y métodos: Este estudio prospectivo incluyó 40 pacientes consecutivos (27 mujeres/13 hombres, 68,10±10,27 años) con PMR y sospecha de VGV asociada evaluados con 18F-FDG PET/TAC. Los estudios PET/TAC fueron obtenidos 180 minutos después de la inyección intravenosa de 18F-FDG. Se realizó un análisis visual de la intensidad de captación (0-3) en troncos supraaórticos (TSA), aorta torácica (AT), aorta abdominal (AA), arterias ilíacas (AI) y arterias femoro/tibioperoneales (AFT). Se estableció un diagnóstico final de VGV en 26/40 pacientes (65%). Resultados: En los 26 pacientes con diagnóstico de VGV la mayor intensidad de captación de 18F-FDG se objetivó en AT, TSA y AFT. En todos ellos se observó captación en la AT, principalmente grado 2 y 3. En 4 de los 14 sin VGV no se visualizó captación en ninguna región vascular y en los otros 10 solo se observó captación grado 1 en uno o 2 territorios. De los 20 pacientes con VGV previamente tratados, la 18F-FDG PET/TC motivó un cambio terapéutico en 17 (85%). Conclusiones: La 18F-FDG PET/TAC fue una herramienta útil para identificar pacientes con VGV asociada a PMR. La detección de inflamación vascular tuvo un importante impacto, motivando un cambio de tratamiento en un alto porcentaje de los pacientes con VGV

(18)F-FDG PET/CT for the detection of large vessel vasculitis in patients with polymyalgia rheumatica.

PURPOSE: Polymyalgia rheumatica (PMR) may present together with large vessel vasculitis (LVV), and frequently requires a more intensive therapy. The aim of the study was to evaluate the impact of (18)F-FDG PET/CT in the diagnosis and management of LVV associated to PMR. MATERIAL AND METHODS: This prospective study included 40 consecutive patients (27 women/13 men, 68.10±10.27 years) with PMR and suspicion of associated LVV submitted for (18)F-FDG PET/CT. A PET/CT scan was obtained 180 min after (18)F-FDG intravenous injection. A visual analysis was performed on the images. Five vascular regions were evaluated: supra-aortic trunks (SAT), thoracic aorta (TA), abdominal aorta (AA), iliac arteries (IA), and femoral/tibioperoneal arteries (FTA). The intensity of uptake was graded from 0 to 3. A final diagnosis of LVV was established in 26/40 patients (65%). RESULTS: In the 26 patients with a diagnosis of LVV, the highest intensity of (18)F-FDG uptake was observed in the TA, SAT, and FTA. All of these patients showed uptake at the TA, with grade 2 and 3 in most cases. In 4 of the 14 patients without LVV, no uptake was observed in any vascular region, and in the other 10 patients only a grade 1 uptake was observed in 1 or to 2 territories. Out of the 20 treated LVV patients, (18)F-FDG PET/CT led to a therapeutic change in 17 (85%). CONCLUSION: (18)F-FDG PET/CT was useful in identifying patients with LVV associated to PMR. The detection of vascular inflammation had an important impact, and led to a change of treatment in a high percentage of patients with LVV.

Assessment of aortitis by semiquantitative analysis of 180-min 18F-FDG PET/CT acquisition images.

PURPOSE: The aim of this study was to evaluate the contribution of semiquantitative analysis of 180-min (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT images for the assessment of aortitis in cases of suspected large vessel vasculitis (LVV) and to establish a threshold index for application in the clinical setting. METHODS: This prospective study included 43 patients (mean age 67.5 ± 12.9 years) with suspicion of LVV (25 with a final diagnosis of aortitis). (18)F-FDG PET/CT scan was acquired 180 min after injection of 7 MBq/kg of (18)F-FDG. A semiquantitative analysis was performed calculating the aortic wall maximum standardized uptake value (SUVmax) (T), the lumen SUVmax (B) and the target to background ratio (TBR). These results were also compared with those obtained in a control population. RESULTS: The mean aortic wall SUVmax was 2.00 ± 0.62 for patients with aortitis and 1.45 ± 0.31 for patients without aortitis (p < 0.0001). The TBR was 1.66 ± 0.26 for patients with aortitis and 1.24 ± 0.08 for patients without aortitis (p < 0.0001). The differences were also statistically significant when the patients with aortitis and controls were compared. Receiver-operating characteristic (ROC) analysis revealed that the area under the curve was greater for the TBR than for the aortic wall SUVmax (0.997 vs 0.871). The highest sensitivity and specificity was obtained for a TBR of 1.34 (sensitivity 100%, specificity 94.4%). CONCLUSION: Semiquantitative analysis of PET/CT images acquired 180 min after (18)F-FDG injection and the TBR index of 1.34 show very high accuracy and, therefore, are strongly recommended for the diagnosis of aortitis in the clinical setting.

Contribution of V/Q SPECT to planar scintigraphy in the diagnosis of pulmonary embolism / Contribución de la SPECT V/Q a la gammagrafía planar en el diagnóstico del tromboembolismo pulmonar

Aim: To evaluate the feasibility of V/Q SPECT and analyze its contribution to planar V/Q lung scintigraphy in the diagnosis of pulmonary embolism (PE). Material and methods: A total of 109 patients with suspected PE showing Wells score > 2 and elevated D-dimer were studied. The V/Q could not be completed in 7 patients, so they were excluded. Ventilation and perfusion scans were done using Technegas and 99mTc-MAA. Planar study included 8 projections on a 256 × 256 matrix and 128 projections on a 128 × 128 matrix were acquired for the SPECT study, applying an iterative method. Planar images were interpreted according to modified PIOPED criteria, and SPECT by the guidelines of the EANMMI. The results with both techniques were compared. Results: V/Q planar scintigraphy and SPECT could be performed in 102 patients. V/Q planar scintigraphy was considered "diagnostic" in 39 of the 102 patients, and "non-diagnostic" in 63. Of the 39 "diagnostic" studies, 31 were reported as high probability of PE and 8 as normal. Of the 63 "non-diagnostic", 26 corresponded to intermediate, 29 to low, and 8 to very low probability. The SPECT study was "diagnostic" in 97 and indeterminate in only 5. All patients with a high probability planar scintigraphy had a positive SPECT. In the 8 patients with a normal planar scintigraphy SPECT was negative in 5 and positive in 3. In the 63 patients with a "non-diagnostic" planar scintigraphy SPECT was "diagnostic" in 58 of them, positive in 17 and negative in 41. Conclusion: V/Q SPECT is a feasible technique as it was performed in 102 of the 109 patients who were enrolled in the study (94%). The addition of V/Q SPECT to planar V/Q decreases the number of "non-diagnostic" reports from 62% in planar scintigraphy to 4.9% in SPECT. Therefore, V/Q SPECT should be included in the diagnosis approach of PE due to its high diagnostic yield (AU)

Objetivo: Evaluar la factibilidad de la SPECT V/Q y analizar su contribución a la gammagrafía planar en el diagnóstico del tromboembolismo pulmonar (TEP). Material y métodos: Estudio en 109 pacientes con sospecha de TEP, con escala de Wells > 2 y dímero D elevado. Se excluyeron 7 pacientes porque no pudieron completar el estudio. Para la gammagrafía de ventilación se empleó Technegas y para el estudio de perfusión 99mTc-MAA. El estudio planar incluyó 8 proyecciones en matriz 256 × 256, en la SPECT se adquirieron 128 proyecciones en matriz 128 × 128, aplicándose una reconstrucción iterativa. Las imágenes planares fueron interpretadas según criterios PIOPED modificados y la SPECT según la guía de la EANMMI. Se compararon los resultados obtenidos entre ambas técnicas. Resultados: Fue posible realizar el estudio V/Q planar y la SPECT en 102. La gammagrafía planar V/Q fue considerada «diagnóstica» en 39 de los 102 pacientes, y «no diagnóstica» en 63. De las 39 gammagrafías «diagnósticas», 31 fueron de alta probabilidad para TEP y 8 fueron normales. De las 63 gammagrafías «no diagnósticas», 26 fueron probabilidad intermedia, 29 baja y 8 muy baja probabilidad. La SPECT fue diagnóstica en 97 e indeterminada solo en 5. En todos los pacientes con alta probabilidad en la gammagrafía planar la SPECT fue positiva. En los 8 pacientes con gammagrafía planar normal la SPECT fue negativa en 5 y positiva en 3. En 63 pacientes con gammagrafía planar «no diagnóstica», la SPECT fue «diagnóstica» en 58 de ellos, siendo positiva en 17 y negativa en 41. Conclusión: La SPECT V/Q es una técnica factible, ya que se realizó en 102 de los 109 pacientes incluidos en el estudio (94%). La incorporación de la SPECT V/Q a la gammagrafía planar disminuyó el número de informes «no diagnóstico» de un 62% en la gammagrafía planar a un 4,9% con la SPECT. Por lo tanto la SPECT V/Q debe incluirse en el diagnóstico de TEP por su alto rendimiento diagnóstico (AU)

Comparison of 99mTc-sestamibi and 11C-methionine PET/CT in the localization of parathyroid adenomas in primary hyperparathyroidism / Comparación del 99mTc-sestamibi y 11C-metionina PET/TC en la localización del adenoma de paratiroides en el hiperparatiroidismo primario

Aim: To evaluate the usefulness of 11C-methionine PET/CT (MET) in the localization of the parathyroid adenomas and to compare the results with those obtained with the conventional technique in double-phase 99mTc-sestamibi scintigraphy (MIBI). We evaluated the optimal timing to acquire MET images. Material and methods: A prospective study that included 14 patients (mean age: 65.5 ± 9.7 years) with primary hyperparathyroidism (PH) who underwent surgery was performed. Mean serum iPTH was 215.8 ± 108 pg/mL and serum calcium 10.8 ± 0.9 mg/dL. MIBI (planar and SPECT) was obtained 10 min and 2–3 h after injection of 740 MBq (20 mCi) of 99mTc-sestamibi. MET was obtained 10 min and 40 min after injection of 740 MBq (20 mCi) of 11C-methionine. MIBI and MET images were visually evaluated and compared. A score for 10 min and 40 min MET images from 0 (no abnormal uptake) to 3 (intense uptake) was assigned. Results: MIBI and MET were positive and concordant in 11/14 patients and in 10 of them the parathyroid adenoma was correctly localized. In 3/14 MIBI was positive and MET negative (MIBI correctly localized the parathyroid adenoma in 2 of them). According to the timing of MET imaging acquisition, the 10 min and 40 min acquisition showed the same score in 10 patients, it was higher at 10 min acquisition in 3 and in 1 the parathyroid adenoma was only detected at 40 min acquisition. Conclusion: MIBI remains the technique of choice for the localization of parathyroid adenomas in patients with PH. MET may play a complementary role in selected patients. Delayed acquisition should be included in the MET protocol when the early acquisition is negative (AU)

Objetivos: Evaluar la utilidad de la 11C-metionina PET/TC (MET) en la localización de adenoma de paratiroides comparado con la técnica convencional en doble fase con 99mTc-sestamibi (MIBI). Evaluar el tiempo adecuado para la adquisición de imágenes MET. Material y métodos: Este estudio prospectivo incluyó 14 pacientes (edad: 65,5 ± 9,7 años) con hiperparatiroidismo primario (HPTP) sometidos a cirugía. La iPTH fue de 215,8 ± 108 pg/mL y el calcio sérico 10,8 ± 0,9 mg/dL. El MIBI (planar, SPECT) fue realizado a los 10 min y 2-3 horas tras la inyección de 740 MBq (20 mCi) de MIBI. La MET fue realizada 10 min y 40 min tras la inyección de 740 MBq (20 mCi) de MET. Las imágenes fueron evaluadas visualmente y comparadas. Las imágenes con MET a 10 min y 40 min fueron valoradas según el grado de captación (0[no captación] a 3[intensa]). Resultados: MIBI y MET fueron positivos y concordantes en 11/14 pacientes, en 10 de ellos el adenoma de paratiroides fue correctamente localizado. En 3/14 el MIBI fue positivo y la MET negativa (el MIBI localizó correctamente 2). Con respecto al tiempo de adquisición imágenes MET a los 10 min y 40 min se observó la misma puntuación en 10 pacientes, fue mayor a los 10 min en 3 y en un paciente sólo fue positivo a los 40 min. Conclusiones: El MIBI continúa siendo la técnica de elección para la localización del adenoma de paratiroides en pacientes con HPTP. La MET podría tener un papel complementario en pacientes seleccionados. La adquisición tardía de la MET debería ser incluida cuando la imagen precoz sea negativa (AU)

Contribution of V/Q SPECT to planar scintigraphy in the diagnosis of pulmonary embolism.

AIM: To evaluate the feasibility of V/Q SPECT and analyze its contribution to planar V/Q lung scintigraphy in the diagnosis of pulmonary embolism (PE). MATERIAL AND METHODS: A total of 109 patients with suspected PE showing Wells score>2 and elevated D-dimer were studied. The V/Q could not be completed in 7 patients, so they were excluded. Ventilation and perfusion scans were done using Technegas and (99m)Tc-MAA. Planar study included 8 projections on a 256×256 matrix and 128 projections on a 128×128 matrix were acquired for the SPECT study, applying an iterative method. Planar images were interpreted according to modified PIOPED criteria, and SPECT by the guidelines of the EANMMI. The results with both techniques were compared. RESULTS: V/Q planar scintigraphy and SPECT could be performed in 102 patients. V/Q planar scintigraphy was considered "diagnostic" in 39 of the 102 patients, and "non-diagnostic" in 63. Of the 39 "diagnostic" studies, 31 were reported as high probability of PE and 8 as normal. Of the 63 "non-diagnostic", 26 corresponded to intermediate, 29 to low, and 8 to very low probability. The SPECT study was "diagnostic" in 97 and indeterminate in only 5. All patients with a high probability planar scintigraphy had a positive SPECT. In the 8 patients with a normal planar scintigraphy SPECT was negative in 5 and positive in 3. In the 63 patients with a "non-diagnostic" planar scintigraphy SPECT was "diagnostic" in 58 of them, positive in 17 and negative in 41. CONCLUSION: V/Q SPECT is a feasible technique as it was performed in 102 of the 109 patients who were enrolled in the study (94%). The addition of V/Q SPECT to planar V/Q decreases the number of "non-diagnostic" reports from 62% in planar scintigraphy to 4.9% in SPECT. Therefore, V/Q SPECT should be included in the diagnosis approach of PE due to its high diagnostic yield.

Comparison of 99mTc-sestamibi and 11C-methionine PET/CT in the localization of parathyroid adenomas in primary hyperparathyroidism.

AIM: To evaluate the usefulness of (11)C-methionine PET/CT (MET) in the localization of the parathyroid adenomas and to compare the results with those obtained with the conventional technique in double-phase (99m)Tc-sestamibi scintigraphy (MIBI). We evaluated the optimal timing to acquire MET images. MATERIAL AND METHODS: A prospective study that included 14 patients (mean age: 65.5 ± 9.7 years) with primary hyperparathyroidism (PH) who underwent surgery was performed. Mean serum iPTH was 215.8 ± 108 pg/mL and serum calcium 10.8 ± 0.9 mg/dL. MIBI (planar and SPECT) was obtained 10 min and 2-3h after injection of 740 MBq (20 mCi) of (99m)Tc-sestamibi. MET was obtained 10 min and 40 min after injection of 740 MBq (20 mCi) of (11)C-methionine. MIBI and MET images were visually evaluated and compared. A score for 10 min and 40 min MET images from 0 (no abnormal uptake) to 3 (intense uptake) was assigned. RESULTS: MIBI and MET were positive and concordant in 11/14 patients and in 10 of them the parathyroid adenoma was correctly localized. In 3/14 MIBI was positive and MET negative (MIBI correctly localized the parathyroid adenoma in 2 of them). According to the timing of MET imaging acquisition, the 10 min and 40 min acquisition showed the same score in 10 patients, it was higher at 10 min acquisition in 3 and in 1 the parathyroid adenoma was only detected at 40 min acquisition. CONCLUSION: MIBI remains the technique of choice for the localization of parathyroid adenomas in patients with PH. MET may play a complementary role in selected patients. Delayed acquisition should be included in the MET protocol when the early acquisition is negative.