Search

Table S2. Exploratory analysis. (DOCX 23 kb)

Figure S4. APOE and plasma Aβ ratios. The effects of APOE genotype on plasma Aβ levels using ANOVA between APOE ε4 carriers and noncarriers in a boxplot representation with outlier analysis. (PDF 93 kb)

Table S3. Regression analyses between Aβ plasma ratios and FBB-PET SUVR. (DOCX 18 kb)

Table S5. Interaction between APOE and L_TP42/40. (DOCX 14 kb)

Figure S2. Scatter plots for FBB-PET global SUVR and Aβ plasma ratios in SCD subjects. Correlations between plasma biomarkers and brain Aβ burden. Biomarkers values plotted against SUVR values from FBB-PET imaging: FP42/40 (A), BP42/40 (B), FP42/TP42 (C), and FP40/TP40 (D). (PDF 286 kb)

Figure S3. Linear regression between FBB-PET and Aβ TP42/40 plasma ratio in APOE ε4 stratification SCD population. A) APOE ε4 carriers; B) APOE ε4 noncarriers. (PDF 115 kb)

Figure S1. A) Distribution of FBB-PET and plasma ratios. B) Shapiro-Wilk test for FBB-PET and plasma ratios. C) Log distributions FBB-PET and plasma ratios. D) Shapiro-Wilk test for logarithmic FBB-PET and log-plasma ratios. A, B) Distributions and Shapiro-Wilk test for plasma ratios and FBB-PET to test normality. C, D) Distributions and Shapiro-Wilk test for transformed to logarithmic plasma ratios and FBB-PET to test normality. (PDF 299 kb)

Table S4. ANOVAs comparing APOE ε4 carriers vs noncarriers. (DOCX 14 kb)

Standardised uptake value (SUV) and volumetric parameters such as metabolic tumour volume (MTV) and total lesion glycolysis (TLG) fromA pre-treatment PET/CT was performed on 18 patients with suspected or newly diagnosed EOC. Maximum SUV (SUVmax), mean SUV (SUVmean), whole-body MTV (wbMTV), and whole-body TLG (wbTLG) with a threshold of 30% and 40% of the SUVmax were obtained. Furthermore, Ki67 index (mean and hotspot) was estimated in tumour tissue specimens. Immunohistochemical findings were correlated with PET parameters.The mean age was 57.0 years old (standard deviation 13.6 years). A moderate correlation was observed between mean Ki67 index and SUVmax (r=0.392), SUVmean 30% (r=0.437), and SUVmean 40% (r=0.443), and also between hotspot Ki67 index and SUVmax (r=0.360), SUVmean 30% (r=0.362) and SUVmean 40% (r=0.319). There was a weaker correlation, which was inversely negative, between mean and hotspot Ki67 and volumetric PET parameters. However, no statistical significant differences were found for any correlations.SUVmax and SUVmean were moderately correlated with Ki67 index, whereas volumetric PET parameters overall, showed a weaker correlation. Thus, SUVmax and SUVmean could be used to assess tumour aggressiveness in pre-treatment EOC.

Introduction Subjective cognitive decline (SCD) has been proposed as a potential preclinical stage of Alzheimer's disease (AD). Nevertheless, the genetic and biomarker profiles of SCD individuals remain mostly unexplored. Methods We evaluated apolipoprotein E ( APOE ) e4's effect in the risk of presenting SCD, using the Fundacio ACE Healthy Brain Initiative (FACEHBI) SCD cohort and Spanish controls, and performed a meta-analysis addressing the same question. We assessed the relationship between APOE dosage and brain amyloid burden in the FACEHBI SCD and Alzheimer's Disease Neuroimaging Initiative cohorts. Results Analysis of the FACEHBI cohort and the meta-analysis demonstrated SCD individuals presented higher allelic frequencies of APOE e4 with respect to controls. APOE dosage explained 9% (FACEHBI cohort) and 11% (FACEHBI and Alzheimer's Disease Neuroimaging Initiative cohorts) of the variance of cerebral amyloid levels. Discussion The FACEHBI sample presents APOE e4 enrichment, suggesting that a pool of AD patients is nested in our sample. Cerebral amyloid levels are partially explained by the APOE allele dosage, suggesting that other genetic or epigenetic factors are involved in this AD endophenotype.

Resume La tomographie par emission de positons (TEP) permet d’observer le fonctionnement du systeme nerveux central (SNC). Elle permet d’obtenir des images du flux sanguin, du metabolisme et des systemes de neurotransmission. Elle quantifie ces parametres de facon tres exacte et reproductible. Dans la recherche, on l’utilise dans l’etude de la physiologie du SNC, de la physiopathologie de maladies neurologiques et psychiatriques (surtout, dans l’evaluation de la reponse aux nouveaux traitements) et dans la conception et la recherche de nouveaux medicaments. Le seul traceur TEP utilise en clinique est le FDG. Selon des criteres fondes sur des donnees probantes, les indications cliniques des explorations du cerveau par TEP sont les suivantes : evaluation de gliomes et de tumeurs cerebrales deja traites, evaluation prechirurgicale des epilepsies partielles resistantes aux traitements medicaux et diagnostic differentiel des demences de type Alzheimer et des demences frontotemporales, lorsqu’il est impossible de les distinguer cliniquement.

Aim of the present study was to evaluate the usefulness of 11C-choline PET/CT for detecting lymphatic or haematogenous spread and for planning radiotherapy in patients with medium-to-high risk prostate cancer.We have included 61 consecutive patients recently diagnosed with cancer prostate by biopsy. All patients were classified as medium-to-high risk: Gleason: 7-9; PSA: 6.3-30.4 ng/mL; stage T2c (N.=20) or stage T3 (N.=41). Image acquisition began 5 min after intravenous injection of 11C-choline (656+119 MBq), starting at the pelvis and continuing craniocaudally. Images were interpreted visually to evaluate uptake by the prostate gland. Lymph nodes with 11C-choline uptake were considered invaded, regardless of their size. Bone lesions were considered positive when they showed greater focal uptake than the surrounding bone. In patients with evidence of lymph-node invasion or bone metastases (15 patients), disease was classified as locoregional, oligometastatic, or multimetastatic.All patients had prostate gland uptake (20 focal, 8 bifocal, and 33 multifocal). Extraprostatic disease was present in 15 patients (24.6%), as follows: 9 (60%) in a single location: in an infradiaphragmatic lymph node (N.=6), in a supradiaphragmatic lymph node (N.=1), and in bone (M1) (N.=2). Six (40%) as multifocal invasion: with both infra- and supradiaphragmatic lymph node involvement (N.=2); with infradiaphragmatic lymph node involvement and M1 bone metastases (N.=3); and infra- and supradiaphragmatic lymph node involvement plus M1 bone metastases (N.=1). Disease was classified as locoregional (N.=6), oligometastatic (N.=5), and multimetastatic (N.=4). The 11 (73.3%) patients with locoregional and oligometastatic disease were selected to undergo intensity-modulated radiation therapy with dose escalation based on the PET findings.Our results suggest that 11C-choline PET/CT is a useful one-stop diagnostic procedure for evaluating patients with medium/high risk prostate cancer scheduled for radical treatment. 11C-choline PET/CT can reliably rule out lymph node involvement and remote metastases, allowing to select candidates for radiotherapy and to plan their treatment.

Resumen Introduccion Los tumores del estroma gastrointestinal (GIST) pueden presentarse como una enfermedad diseminada. Un inhibidor de la tirosina-quinasa (Glivec) ha obtenido respuestas espectaculares en pacientes con enfermedad irresecable. El objetivo de este estudio fue mostrar la utilidad de la tomografia por emision de positrones-fluorodesoxiglucosa (PET-FDG) en la estadificacion inicial, en la recurrencia y en la valoracion precoz de la respuesta al Glivec. Material y metodos Realizamos 48 estudios con PET en 27 pacientes (19 varones/edad media = 56a): estadificacion inicial (n = 13), valoracion de enfermedad recurrente (n = 15) y respuesta al tratamiento con imatinib (n = 20). La valoracion de los estudios se realizo mediante analisis visual y semicuantitativo (SUV [standardized uptake value]). Los resultados se confirmaron mediante seguimiento, pruebas de imagen y/o histologia. Resultados En la estadificacion inicial, la PET mostro una mayor extension de la enfermedad en 3/10 de los pacientes evaluados. En otros 3 pacientes evitamos la administracion adyuvante de imatinib. La PET mostro una correcta respuesta terapeutica en once de los trece pacientes evaluados (completa en siete y parcial en cuatro). La disminucion media del SUV en los respondedores parciales fue del 60 %. Dos pacientes no mostraron disminucion de la captacion del trazador con dosis de 400 ni de 800 mg de Glivec, permaneciendo el SUV estable y/o aumentado la intensidad de captacion en algunas lesiones. Asimismo, la PET detecto una recurrencia tumoral en un paciente. Conclusiones Este estudio muestra como la PET-FDG es una tecnica util en la valoracion precoz de la respuesta terapeutica al imatinib. La PET puede ser tambien eficaz en la deteccion y re-estadificacion de la enfermedad recurrente.

Resumen Objetivos Estudiar el efecto de la dispersion de fotones en la cuantificacion de los cambios relativos en estudios longitudinales de tomografia por emision de positrones (PET) cerebral utilizando 18F-FDG. Material y metodos Se utilizo un maniqui numerico de Zubal y se simularon dos estudios, uno de referencia (basal) y otro en el que habia un aumento/disminucion de la captacion en una region situada en el cortex cingulado anterior. Para obtener los sinogramas se utilizo SimSET, un codigo Monte Carlo que permite la simulacion de estudios de tomografia de emision. Para evaluar el efecto de la dispersion se almacenaron en ficheros separados los fotones primarios que no sufren ningun tipo de interaccion y los fotones dispersados despues de producirse una o mas interacciones. La reconstruccion se realizo utilizando un algoritmo iterativo basado en subconjuntos ordenados OSEM-2D. Se calcularon los cambios relativos de captacion a partir de las imagenes reconstruidas con fotones totales (primarios y dispersados) y de las obtenidas unicamente con fotones primarios. Resultados Se obtuvo una relacion lineal entre los valores de cambio relativo calculados y los teoricos, tanto para imagenes con fotones totales como con fotones primarios. En el caso en el que se consideraron solo fotones primarios la recuperacion del cambio relativo fue del 91% ± 0,5 %, mientras que la presencia de fotones dispersados produce una recuperacion del 79% ± 0,4%. Conclusiones Nuestros resultados muestran que la presencia de fotones dispersados producen una subestimacion de los valores de captacion relativa del 12% ± 0,7 % y, en consecuencia, evidencian la importancia de la correccion de esta degradacion para mejorar la exactitud de la cuantificacion.

En la actualidad las exploraciones neurologicas mediante tomografia computarizada por emision de fotones simples (SPECT) y tomografia por emision de positrones (PET) no se utilizan en el diagnostico de estado vegetativo persistente (EVP). Hay, no obstante, mas referencias bibliograficas sobre el uso de la PET que de la SPECT en el EVP. La PET detecta las alteraciones del metabolismo cerebral de la glucosa y del flujo sanguineo cerebral que presentan los pacientes con EVP postanoxia. La PET puede ser empleada para valorar la funcion cerebral residual de los pacientes con EVP.

Functional Neuroimaging has been traditionally used in research for patients with different Parkinsonian syndromes. However, the emergence of commercial radiotracers together with the availability of single photon emission computed tomography (SPECT) and, more recently, positron emission tomography (PET) have made them available for clinical practice. Particularly, the development of clinical evidence achieved by functional neuroimaging techniques over the past two decades have motivated a progressive inclusion of several biomarkers in the clinical diagnostic criteria for neurodegenerative diseases that occur with Parkinsonism. However, the wide range of radiotracers designed to assess the involvement of different pathways in the neurodegenerative process underlying Parkinsonian syndromes (dopaminergic nigrostriatal pathway integrity, basal ganglia and cortical neuronal activity, myocardial sympathetic innervation), and the different neuroimaging techniques currently available (scintigraphy, SPECT and PET), have generated some controversy concerning the best neuroimaging test that should be indicated for the differential diagnosis of Parkinsonism. In this article, a panel of nuclear medicine and neurology experts has evaluated the functional neuroimaging techniques emphazising practical considerations related to the diagnosis of patients with uncertain origin parkinsonism and the assessment Parkinson's disease progression.

Quantification of neurotransmission Single-Photon Emission Computed Tomography (SPECT) studies of the dopaminergic system can be used to track, stage and facilitate early diagnosis of the disease. The aim of this study was to implement QuantiDOPA, a semi-automatic quantification software of application in clinical routine to reconstruct and quantify neurotransmission SPECT studies using radioligands which bind the dopamine transporter (DAT). To this end, a workflow oriented framework for the biomedical imaging (GIMIAS) was employed. QuantiDOPA allows the user to perform a semiautomatic quantification of striatal uptake by following three stages: reconstruction, normalization and quantification. QuantiDOPA is a useful tool for semi-automatic quantification inDAT SPECT imaging and it has revealed simple and flexible.

La medicina nuclear interviene en el manejo clinico de los pacientes con cancer diferenciado de tiroides. El yodo-131 refleja el funcionalismo tiroideo y permite detectar la presencia de tejido tiroideo y de tumor residual tras la tiroidectomia total. La administracion de dosis altas de yodo-131 destruye los restos tiroideos tumorales e identifica y permite tratar nuevas lesiones tumorales locales o a distancia. Recientemente han aparecido nuevas tecnicas que han variado ostensiblemente los procedimientos de actuacion en estos pacientes. Entre ellas destaca el estimulo de tejido tiroideo con hormona estimuladora del tiroides (TSH) recombinante con el fin de evitar los sintomas derivados del hipotiroidismo previo al yodo-131 o la administracion de acido retinoico como factor de rediferenciacion tumoral. En algunos casos, pueden tener relevancia la determinacion de tiroglobulina o los estudios con PET con el objetivo de mejorar la exactitud diagnostica en estos pacientes. En este trabajo se revisa la situacion actual de la medicina nuclear en el diagnostico, tratamiento y seguimiento evolutivo de este tipo de tumores.

La tomografia por emision de positrones (PET) es una tecnica tipica de medicina nuclear, ya que requiere la inyeccion previa de un trazador radiactivo emisor de positrones. La riqueza de la emision fotonica, tras la aniquilacion de los positrones, y la especial configuracion de los tomografos PET, disenados para la deteccion por coincidencia, resultan en una gran eficiencia de contaje, indispensable para obtener imagenes de muy buena resolucion morfologica. La posibilidad de marcar con radioisotopos como C-11, O-15, N-13 y F-18 hace que muchas moleculas endogenas como precursores, sustratos, enzimas, ligandos, transmisores, receptores, etc., se conviertan en trazadores PET. La PET permite visualizar y medir, sin alterarlos, numerosos procesos fisiologicos celulares. La PET obtiene in vivo imagenes bioquimicas o moleculares comparables a las que se obtienen ex vivo por autorradiografia. Asi, desde que aparecio en la decada de los setenta, ha sido una herramienta de trabajo ampliamente utilizada para la investigacion biomedica. La necesidad de disponer de ciclotron para la produccion de muchos de sus trazadores ha limitado el uso de la PET. La produccion centralizada y el suministro externo de fluoro-deoxi-glucosa-F18 (FDG) han hecho desaparecer la dependencia obligada del ciclotron. Con el abaratamiento consiguiente de los costes, cada vez mas usuarios han tenido acceso a la PET y se han podido definir sus distintos usos clinicos. La aplicacion de la PET en el paciente oncologico es la que mas rendimiento clinico y mejor relacion coste/beneficio tiene1.

Bronchial carcinoid tumor is the most frequent occult source of ectopic ACTH-dependent Cushing’s syndrome, but its initial localization may be very difficult, as well as its postoperative follow-up. We here present the case of a 21 -year-old man with Cushing’s syndrome and biochemical findings suggesting an ectopic source of ACTH (lack of inhibition of Cortisol after overnight 8-mg dexametha-sone supression test, and lack of response to h-CRH challenge). Chest CT-scan showed a node adjacent to the left lung hilium whose nature was confirmed by uptake of 111Indium-DTPA labelled octreotide scintigraphy. Surgical resection of the tumor consisted in an upper lobectomy of the left lung. Microscopic examination identified a typical carcinoid tumor. After surgery pituitary-adrenal function normalized and a second scintigraphy offered additional data on the absence of tumor remnants.

The current protocols include the bone scintigraphy and choline PET/CT to localize recurrence in patients having elevated serum PSA after treatment for prostate cancer. Both methods show good agreement in the diagnosis of bone metastases, however conflicting results can be found. We present three cases in which a PET/CT was performed with (18)F-Fluoride due to disagreement between the bone scintigraphy and (11)C-Choline PET/CT. The (18)F-Fluoride PET/CT was capable of confirming the existence of bone metastasis in all of them, so it may be an alternative to the MRI as a tracer of second bone imaging modality, although its use is limited by cost and availability.

To assess the value of intraoperatory radioguided probe detection to guide surgical resection of malignant lesions previously detected by (18)F-FDG PET-CT.Twelve consecutive patients with suspected tumor recurrence detected by (18)F-FDG PET-CT considered resectable were enrolled in the study. Ultrasound guided fine needle aspiration (FNA) before surgery was performed in 6 patients and CT guided biopsy was performed in 1 patient. In 5 patients with accessible lesions, a radioguided occult lesion localization (ROLL) technique was performed after injection of (99m)Tc-colloid (1.7-2.4 mCi) inside the lesion under ultrasound or CT guidance, pre-operatively. Radioguided surgical detection was then carried out 19-24 hours afterwards using the gamma probe. In 7 patients with non-accessible needle lesions or multiple lesions, 9.5-10.5 mCi of (18)F-FDG were injected 3-5 hours before radioguided surgery using a PET-dedicated probe (Gamma locator DXI-GFE).ROLL technique: All lesions injected with nanocolloid were resected (6 lesions in 5 patients, 1 patient with 2 lesions), and recurrence was histologically confirmed. PET probe: Fourteen out of 16 hypermetabolic lesions detected on the PET-CT were resected. One cervical and one mediastinal lymph node in different patients could not be excised. Histological recurrence was confirmed in 12 out of 14 lesions. In one patient, the 2 lymph nodes excised were inflammatory.(18)F-FDG PET-CT can be key in deciding surgical approach and appropriate radioguided protocol. When lesions are solitary and easily accessible, ROLL technique seems the method of choice. PET probe is more adequate for less accessible lesions.

The aim of this study was to evaluate the utility of positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) in monitoring response in refractory GIST.This multicenter study prospectively evaluated 21 patients with locally advanced and/or metastatic GIST refractory to with high-dose imatinib (800 mg/day) treated with doxorubicin 15-20 mg/m2/weekly for 4 cycles, followed by imatinib maintenance (400 mg/day). CT and FDG-PET were performed at baseline and after completion of therapy.Mean baseline tumor size on CT was 5.9 cm. Median progression-free survival (PFS) was 219 days (range 62-1108). Three out of 21 patients (14%) had partial responses (PR) under RECIST criteria, 12 patients (57%) remained stable (SD) and 6 showed progression (PD) of the disease during treatment (29%). Six patients had PR by FDG-PET, 15 showed SD (n=9) or PD (n=6) based on EORTC criteria. Patients with a PFS6 mo showed a significantly higher ∑SUVmax at baseline (26.04±13.4) than those with PFS≥6 mo (9.82±5.0) (P0.05). A correlation was found between PET response and PFS: PR 14±6.1 mo, SD 5.5±0.8 mo and PD 3.5±4.1 mo (P0.05). A residual SUVmax5 after treatment correlated with improved PFS (314±315 days vs 131±91 days) (P0.01). Survival curves showed a significant association between PET response and PFS (P0.05). Patients with wild-type genotype KIT (KIT-WT) showed a significantly lower baseline SUVmax (5.36±1.4) than non-WT KIT (8.40±3.6) (P0.05).FDG-PET is useful in assessing response of GIST refractory to imatinib and correlates with the presence of KIT-WT. Baseline ∑SUVmax can predict response to treatment in this series.

To evaluate the incidence of (18)F-FDG focal uptake in the myocardium as well as its correlation with coronary vessel calcifications.A total of 130 patients who underwent an oncological PET/CT study were reviewed retrospectively. Sixty-five had undergone a myocardial perfusion study because of clinical suspicion of coronary artery disease (group 1). There were no significant differences in age and gender regarding another group of the same series (n=65; group 2). Focal myocardial (18)F-FDG uptake and the presence of coronary vessel calcifications were identified by 2 independent observers.Group 1: in 18 out of 65 patients (28%) focal myocardial (18)F-FDG uptake was identified (5 had 2 foci; total: 23 foci). In 43 out of 65 studies (66%), calcification was identified in the coronary vessels. Group 2: in 6 out of 65 patients (9%) focal myocardial (18)F-FDG uptake was identified (1 had 2 foci; total: 7 foci). In 17 out of 65 studies (26%), calcification was identified in the coronary vessels. Comparative analysis: focal myocardial (18)F-FDG uptake and coronary vessel calcifications were more frequent in the group 1 patients (p0.01). There was no correlation between the presence of coronary vessel calcifications and focal myocardial (18)F-FDG uptake in individual patients in both groups (group 1: p=0.7; group 2: p=0.163).PET/CT allows simultaneous assessment of focal myocardial (18)F-FDG uptake and myocardial vessel calcifications. Patients with clinical suspicion of coronary artery disease have a higher incidence of focal myocardial (18)F-FDG uptake and coronary calcifications. However, (18)F-FDG focal uptake is often observed in sites remote from those with calcification.

To determine the impact of an additional inspiration CT scan on the conventional ¹⁸F-FDG PET-CT protocol in the detection of small pulmonary nodules.One hundred consecutive patients who presented with one or various nodules were studied. Whole-body PET-CT was performed using Gemini (Philips). CT acquisition parameters were 120 kV/25 mAs, the same as those for the transmission/fusion CT (mild expiration) and inspiratory CT.A total of 188 nodules were detected in the inspiratory CT with sizes between 0.3-3 cm. Non-inspiratory CT did not show 20/188 nodules (10.6%) with sizes between 0.3-1cm, this corresponding to 17 patients. The most frequent localization of non-detectable nodules in non-inspiratory CT was the lower lobes. ¹⁸F-FDG uptake was detected by the PET in 83.9% and 72% of nodules with1 cm and between 0.7 and 1cm, respectively. However, only 10.5% of nodules0.7 cm showed increased metabolic activity.In selected patients, inspiratory CT added to conventional PET-CT significantly improves the detection of small nodules (10.6%), especially in those lesions located in the lower lobes, due to respiratory movements, and may have an impact on patient management.

To compare the diagnostic accuracy of PET/CT with (18)F-FDG and (11)C-choline for early detection and localization of recurrent prostate cancer.Thirty-eight patients with increased PSA levels (0.8-9.5 ng/ml) after radical treatment for prostate cancer (surgery n = 20/radiation therapy n = 18) were included. Ten patients were on hormone therapy. All patients underwent a PET/CT with (11)C-choline and (18)F-FDG, respectively, on the same day. The PET imaging findings were compared with histopathology (n = 10); PSA monitoring (n = 21) and/ or other methods (n = 7).Focal uptake of (11)C-choline was detected in 26 patients (68%), and focal uptake of (18)F-FDG was detected in 13 patients (34%). The (11)C-choline uptake in 14 patients was suggested local recurrence, whereas this was true in only 4 patients (48%) with (18)F-FDG. Pelvic lymph nodes were detected with (11)C-choline PET/CT in 8 patients and only in 4 patients (50%) with (18)F-FDG. Mediastinal involvement was detected in 5 patients with (11)C-choline and 3 patients (60%) with (18)F-FDG. Focal bone involvement was detected in 3 patients with (11)C-choline and (18)F-FDG. (11)C-choline was able to detect 40% of recurrences in patients with PSA1 ng/ml, 50% of recurrences in patients with PSA 1-4 ng/ml and 87% of recurrences with PSA4 ng/ml. Sensitivity of (11)C-choline was higher for surgically treated patients, with no significant differences found between patients with and without hormone therapy.(11)C-choline PET/CT was useful for the detection of biochemical recurrence of prostate cancer, with higher yielding as compared to (18)F-FDG. (11)C-choline sensitivity was clearly related to PSA levels, was higher in patients with surgery and did not seem to be modified by hormonal therapy. Disease staging with (11)C-choline showed direct impact for the selection of the most appropriate therapeutic approach.

We present the case of a 57-year old woman diagnosed of papillary thyroid carcinoma and treated with thyroidectomy followed by radioiodine (I-131) on two occasions. Follow-up radioiodine scan showed disease in right cervical region, confirmed by fine needle aspiration (FNA) and treated with lymphadenectomy. Due to thyroglobulin elevation, I-131 scan negative and inconclusive cervical ultrasonography/CT scan, we conducted a CT/PET study that confirmed cervical disease. An additional CT scan that was performed on maximum-inspiration showed four micro-nodules, one of which was not detected by the CT scan on shallow breathing (CT/PET). Post-treatment (I-131) scan confirmed uptake in these localizations. Good fusion between PET and CT images that avoids the errors of attenuation correction, especially in the lung bases, is necessary for correct image interpretation of the CT/PET study. Shallow breathing is necessary in order to obtain optimal image fusion with the CT/PET study, although this is not the best to evaluate pulmonary parenchyma in which an additional inspiratory CT scan improves detection of the pulmonary nodules.

To evaluate the usefulness of 111In-oxine-labelled platelet scan in the therapeutic management of prolonged febrile syndrome in dialysis patients with a non-functional renal allograft.One hundred and fifty-eight patients (94 men, 64 women; mean age 44 +/- 9 years) were studied. Duration of fever was 42 days (range 7-112). A total of 68 % of the patients (107/158) were on low doses of corticosteroids (10 mg/day). Platelet scans were performed 48 hours after reinjection of 111In-ixone-labelled platelets. A platelet uptake index (PUI) was calculated by dividing the cpm/pixel in the allograft by the cpm/pixel in a mirror background. A PUIor = 1.5 was considered as threshold for immunological fever. The final diagnosis of immunological fever was established when it disappeared after transplantectomy, embolization or high doses of corticosteroid therapy. Fever of non-immunological origin was established when it disappeared after antibiotic therapy.In 102/158 patients the fever was considered of immunological origin. In 56/158 patients the fever was considered of non immunological origin. Sensitivity and the specificity of the platelet scan was 80 % and 100 %, respectively. All those patients considered as having fever of immunological origin who had PUI1.5 had been using corticosteroids during platelet scan.111In-labelled platelet scintigraphy is a useful technique in the therapeutic management of prolonged febrile syndrome in dialysis patients with non-functional renal allograft. The use of corticosteroids can reduce the sensitivity of 111In- labelled platelet scan.

Extrapyramidal symptoms and Parkinsonism (PS) are side effects commonly observed with antipsychotic treatment. However, about 24% of never-treated schizophrenic patients may suffer from PS, which contrast with that 1% observed from the general population. 123I-FP-CIT SPECT has probe useful to differentiate degenerative from non-degenerative PS, so it could be interesting using it for establishing the functional state of presynaptic dopamine neurons of these patients.To determine the dopamine transporter binding (DAT) in a homogeneous group of first-episode schizophrenic patients.An open, transversal study. Thirty schizophrenic in-patients and 15 healthy subjects were recruited. Patients were treated with similar doses of risperidone and all subjects were scanned with 123I-FP-CIT. Extrapyramidal symptoms and psychopathological status was assessed by Simpson-Angus, CGI and PANSS. Semi-quantitative analyses of SPECT images were performed using ROIs placed in caudate nucleus, anterior, medium and posterior putamen and occipital cortex.Whole striatum 123I-FP-CIT binding ratio was significantly lower in patients than healthy subjects (t = 2.56, p0.014). This was observed in whole putamen (t = 2.66, p0.011), anterior (t = 2.35, p0.023), medium (t = 2.38, p0.022) and posterior putamen (t = 2.09, p0.042). No differences were observed in caudate nucleus (t = 1.81, p = 0.076). Females obtained higher binding ratios than males (t = -3.13, p0.003). No correlation was observed between 123I-FP-CIT binding ratios and clinical scales.In our series, first episode schizophrenic patients treated with risperidone have a decrease striatal DAT binding assessed with 123I-FP-CIT SPECT. This alteration could be related to their own schizophrenia disease or be secondary to the antipsychotic treatment.

We present the case of a 34-year-old woman diagnosed of an adenosquamous carcinoma of the uterine cervix, stage IIB of the FIGO classification (International Federation of Gynecology and Obstetrics), treated with quimiotherapy, radiotheraphy and brachytheraphy with posterior hysterectomy. A recurrence of the disease was suspected due to the progressive rise of CEA levels. A PET/CT revealed abnormal foci in both ovaries, that had been transposed to avoid lesions due to radiation, and in a left para-aortic adenopathy. The diagnosis of recurrence in these sites was confirmed by biopsy. PET with FDG (F18-fluorodeoxyglucose) is useful in the staging of primary tumour and in the detection of recurrence in uterine cervical carcinoma, with better sensitivity and specificity than CT and MRI. PET/CT improves anatomic resolution and helps to resolve the origin of unclear foci like in the case presented in which ovaries were not in their normal situation due to transposition.

OBJETIVO: Determinar el impacto clínico de la PET en la actitud terapéutica de los pacientes oncológicos. MATERIAL Y MÉTODOS: Hemos incluido en este trabajo los cien primeros estudios oncológicos consecutivos de PET con 18FDG de cuerpo completo (75 varones/22 mujeres, edad media de 67 años) procedentes de un mismo hospital público de nuestra comunidad. El impacto de la PET se calculó mediante los resultados de una encuesta enviada a cada uno de los médicos solicitantes de la prueba. Este cuestionario se diseñó fundamentalmente para valorar el tipo de cambio de tratamiento (intramodalidad/intermodalidad) ocasionado tras los hallazgos de la PET. RESULTADOS: Las tres neoplasias estudiadas más frecuentes fueron: carcinoma broncogénico (34%), neoplasia colo-rectal (24%) y nódulo pulmonar solitario (15%). La PET cambió la actitud terapéutica inicialmente prevista en 53 (55%) de los 97 casos evaluados (tipo intramodalidad en 5 e intermodalidad en 48). Diecisiete pacientes (17.5%) candidatos a cirugía curativa fueron finalmente tratados con un tratamiento sistémico de quimioterapia con o sin radioterapia. Los médicos encuestados consideraron que la PET constituía una herramienta diagnóstica útil en el 69% de los casos y que evitaba maniobras diagnósticas agresivas en 56%. CONCLUSIÓN: En nuestra serie de pacientes, la PET con FDG ha sido una herramienta diagnóstica de gran utilidad. Mejora la estadificación inicial de las neoplasias, en especial del carcinoma broncogénico y estadifica de forma más precisa la recidiva tumoral de diferentes tipos de tumores, especialmente de la neoplasia colo-rectal. De este modo, la PET ayuda a seleccionar el tratamiento óptimo en cada caso, evitando cirugías innecesarias.

To study the effect of photon scattering on the quantification of relative changes of 18F-FDG uptake in longitudinal brain PET studies.Two studies from a numerical Zubal phantom were simulated. One of these was a basal reference study and the other was an activated study showing an increase or decrease in the uptake in a region of the anterior cingulated cortex. SimSET Monte Carlo code was used to simulate PET sinograms. Primary photons, which did not undergo interactions, and scattered photons, which underwent one or more interactions, were stored in separate files to assess the effect of scattering. Reconstruction was carried out using an iterative algorithm based on ordered subsets of projections (OSEM-2D). The relative changes in uptake were calculated from images reconstructed with all the photons (primary and scattered) and from images reconstructed with only primary photons.A linear relationship between the calculated and theoretical values was obtained both for the images reconstructed with all the photons and for those reconstructed with primary photons. Our findings show a relative change recovery of 79% +/- 0.4% for all photons and 91% +/- 0.5% for primary photons only.Our results highlight subestimation of relative changes of 12% +/- 0.7% when scattered photons are used. Thus the importance of correcting this degradation in order to improve quantification is shown.

Nuclear medicine plays an important role in staging and evaluation of the initial extension and response to treatment of bone metastases. In order to accurately read Bone Scintigraphy (BS) and Positron Emission Tomography scan (PET) procedures, it is essential to understand the different behavior of these studies. We present a case report of a woman treated for breast cancer, with suspicion of recurrent disease due to increase of tumor markers. Initial BS showed non-conclusive findings, whereas PET study was consistent with a spread of bone metastases. The patient underwent both procedures again after a course of chemotherapy. Post-treatment BS showed progression of bone lesions, while PET showed good therapeutic response. The PET demonstrates lesions earlier and more effectively than the bone scintigraphy in the evaluation of the therapeutic response of bone metastases.