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Background 18F-NaF positron emission tomography/computed tomography (fluoride PET/CT) is considered the most sensitive technique to detect bone metastasis in prostate cancer (PCa). 68Ga-PSMA-11 (PSMA) PET/CT is increasingly used for staging of PCa. This study primarily aimed to compare the diagnostic performance of fluoride PET/CT and gallium-based PSMA PET/CT in identifying bone metastasis followed by a comparison of PSMA PET/CT with contrast-enhanced CT (CE-CT) in identifying soft tissue lesions as a secondary objective. Methods Twenty-eight PCa patients with high suspicion of disseminated disease following curative treatment were prospectively evaluated. PET/CT examinations using fluoride and PSMA were performed. All suspicious bone lesions were counted, and the tracer uptake was measured as standardized uptake values (SUV) for both tracers. In patients with multiple findings, ten bone lesions with highest SUVmax were selected from which identical lesions from both scans were considered for direct comparison of SUVmax. Soft tissue findings of local and lymph node lesions from CE-CT were compared with PSMA PET/CT. Results Both scans were negative for bone lesions in 7 patients (25%). Of 699 lesions consistent with skeletal metastasis in 21 patients on fluoride PET/CT, PSMA PET/CT identified 579 lesions (83%). In 69 identical bone lesions fluoride PET/CT showed significantly higher uptake (mean SUVmax: 73.1 ± 36.8) compared to PSMA PET/CT (34.5 ± 31.4; p p = 0.004) and lymph node (94% vs 46%, p Conclusion In this prospective comparative study, PSMA PET/CT detected the majority of bone lesions that were positive on fluoride PET/CT. Further, this study indicates better diagnostic performance of PSMA PET/CT to locate soft tissue lesions compared to CE-CT.

18F-NaF positron emission tomography/computed tomography (fluoride PET/CT) is considered the most sensitive technique to detect bone metastasis in prostate cancer (PCa). 68Ga-PSMA-11 (PSMA) PET/CT is increasingly used for staging of PCa. This study primarily aimed to compare the diagnostic performance of fluoride PET/CT and PSMA PET/CT in identifying bone metastasis followed by a comparison of PSMA PET/CT with contrast-enhanced CT (CE-CT) in identifying soft tissue lesions as a secondary objective. Methods: Twenty-eight PCa patients with high suspicion of disseminated disease following curative treatment were prospectively evaluated. PET/CT examinations using fluoride and PSMA were performed. All suspicious bone lesions were counted, and the tracer uptake was measured as standardized uptake values (SUV) for both tracers. In patients with multiple findings, ten bone lesions with highest SUVmax were selected from which identical lesions from both scans were considered for direct comparison of SUVmax. PSA at scan was correlated with findings of both scans. Results: Both scans were negative for bone lesions in 7 patients (25%). Of 699 lesions consistent with skeletal metastasis in 21 patients on fluoride PET/CT, PSMA PET/CT identified 579 lesions (83%). In 69 identical bone lesions fluoride PET/CT showed significantly higher uptake (mean SUVmax:73.1 ± 36.8) compared to PSMA PET/CT (34.5 ± 31.4; p max of PSMA PET/CT (r = 0.58; p = 0.01). No correlation was observed between PSA and fluoride PET/CT measurements. Compared to CE-CT, PSMA PET/CT showed better diagnostic performance in locating local (96% vs 61%, p = 0.004) and lymph node (94% vs 46%, p Conclusion: PSMA PET/CT was able to detect majority of bone lesions that were positive on fluoride PET/CT and was better correlated with PSA at time of scan. Further, this study indicates better diagnostic performance of PSMA PET/CT to locate soft tissue lesions compared to CE-CT.

Twenty-eight PCa patients with high suspicion of disseminated disease following curative treatment were prospectively evaluated. PET/CT examinations using fluoride and PSMA were performed. All suspicious bone lesions were counted, and the tracer uptake was measured as standardized uptake values (SUV) for both tracers. In patients with multiple findings, ten bone lesions with highest SUVBoth scans were negative for bone lesions in 7 patients (25%). Of 699 lesions consistent with skeletal metastasis in 21 patients on fluoride PET/CT, PSMA PET/CT identified 579 lesions (83%). In 69 identical bone lesions fluoride PET/CT showed significantly higher uptake (mean SUVIn this prospective comparative study, PSMA PET/CT detected the majority of bone lesions that were positive on fluoride PET/CT. Further, this study indicates better diagnostic performance of PSMA PET/CT to locate soft tissue lesions compared to CE-CT.

Our aim was to compare the effect that having access, versus not having access, to web-based patient information on 18F-FDG PET/CT has on image quality and on patient satisfaction with their care during and knowledge about the examination, as well as to explore whether patients utilized and were satisfied with the web-based information. Methods: We recruited 148 patients between October 2015 and December 2016 and randomly assigned them to a standard-care group or an intervention group. Both groups received standard information about the 18F-FDG PET/CT examination, but the intervention group also received access to web-based information. A questionnaire was used to evaluate patient satisfaction with, knowledge about, and discomfort during the examination, and a masked assessment of image quality was conducted. Results: Overall satisfaction was high in both groups. The lowest satisfaction was with information about how the patients would receive the results of the examination. More patients in the intervention group than in the standard-care group knew how the 18F-FDG PET/CT examination would be conducted. Descriptive data suggest that image quality was slightly better in the intervention group than in the standard-care group, but none of the outcomes significantly differed between the groups. However, several obstacles were encountered during recruitment that led to insufficient power to detect differences. Also, only 54 of 75 patients (72%) in the intervention group utilized the web-based information. However, those who did utilize the information were satisfied with it and found it helpful. Conclusion: The effects of web-based information need to be investigated in a larger sample of patients. Having access to improved information before undergoing 18F-FDG PET/CT may help patients prepare for and undergo the examination. It may also improve image quality. However, this possibility needs to be investigated using image quality as the primary outcome. The results may be used to improve patient information and care and thereby optimize the 18F-FDG PET/CT procedure.

The resolution and quantitative accuracy of PET are highly influenced by the reconstruction method. Penalized-likelihood estimation algorithms allow for fully convergent iterative reconstruction, generating a higher image contrast than ordered-subsets expectation maximization (OSEM) while limiting noise. In this study, a type of penalized reconstruction known as block-sequential regularized expectation maximization (BSREM) was compared with time-of-flight OSEM (TOF OSEM). Various strengths of noise penalization factor β were tested along with various acquisition durations and transaxial fields of view (FOVs) with the aim of evaluating the performance and clinical use of BSREM for 18F-FDG PET/CT, both quantitatively and in a qualitative visual evaluation. Methods: Eleven clinical whole-body 18F-FDG PET/CT examinations acquired on a digital TOF PET/CT scanner were included. The data were reconstructed using BSREM with point-spread function recovery and β-factors of 133, 267, 400, and 533-and using TOF OSEM with point-spread function-for various acquisition times per bed position and various FOVs. Noise level, signal-to-noise ratio (SNR), signal-to-background ratio (SBR), and SUV were analyzed. A masked evaluation of visual image quality, rating several aspects, was performed by 2 nuclear medicine physicians to complement the analysis. Results: The lowest levels of noise were reached with the highest β-factor, resulting in the highest SNR, which in turn resulted in the lowest SBR. A β-factor of 400 gave noise equivalent to TOF OSEM but produced a significant increase in SUVmax (11%), SNR (22%), and SBR (12%). BSREM with a β-factor of 533 at a decreased acquisition duration (2 min/bed position) was comparable to TOF OSEM at a full acquisition duration (3 min/bed position). Reconstructed FOV had an impact on BSREM outcome measures; SNR increased and SBR decreased when FOV was shifted from 70 to 50 cm. The evaluation of visual image quality resulted in similar scores for reconstructions, although a β-factor of 400 obtained the highest mean whereas a β-factor of 267 was ranked best in overall image quality, contrast, sharpness, and tumor detectability. Conclusion: In comparison with TOF OSEM, penalized BSREM reconstruction resulted in an increased tumor SUVmax and an improved SNR and SBR at a matched level of noise. BSREM allowed for a shorter acquisition than TOF OSEM, with equal image quality.

Positron emission tomography (PET) imaging is used to localize recurrent disease in prostate cancer (PCa). The tracer 68Ga-PSMA-11 visualizes lesions overexpressing prostate-specific membrane antigen (PSMA), while 11C-acetate visualizes lesions with increased anabolic metabolism. The aim of this study was to compare the performance of PSMA-PET and acetate-PET in re-staging patients with biochemical relapse. Thirty PCa patients with prostate-specific antigen (PSA) relapse after primary curative therapy were prospectively evaluated. PET/CT examinations using 11C-acetate and 68Ga-PSMA-11 were performed. Identified lesions were categorized according to anatomical location and PET measurements were correlated with PSA at time of scan. Tumour lesions showed higher semi-quantitative uptake values on PSMA-PET than acetate-PET. PSMA-PET identified more lesions in 11 patients, fewer lesions in eight patients, and identical number of lesions in 11 patients. This study indicates better diagnostic performance of PSMA-PET, particularly in detecting lymph node (81% vs 60%, p = 0.02) and bone metastasis (95% vs 61%, p = 0.0001) compared to acetate-PET. However, 38% of PSMA-expressing metastases appear to be metabolically inactive and 15% of metabolically active metastases lack PSMA expression. Addition of PET with a metabolic tracer, such as 11C-acetate, might be beneficial before making treatment decisions.

Positron emission tomography (PET) imaging is used to localize recurrent disease in prostate cancer (PCa). The tracer 68Ga-PSMA-11 visualizes lesions overexpressing prostate-specific membrane antigen (PSMA), while 11C-acetate visualizes lesions with increased anabolic metabolism. The aim of this study was to compare the performance of PSMA-PET and acetate-PET in re-staging patients with biochemical relapse. Thirty PCa patients with prostate-specific antigen (PSA) relapse after primary curative therapy were prospectively evaluated. PET/CT examinations using 11C-acetate and 68Ga-PSMA-11 were performed. Identified lesions were categorized according to anatomical location and PET measurements were correlated with PSA at time of scan. Tumour lesions showed higher semi-quantitative uptake values on PSMA-PET than acetate-PET. PSMA-PET identified more lesions in 11 patients, fewer lesions in eight patients, and identical number of lesions in 11 patients. This study indicates better diagnostic performance of PSMA-PET, particularly in detecting lymph node (81% vs 60%, p = 0.02) and bone metastasis (95% vs 61%, p = 0.0001) compared to acetate-PET. However, 38% of PSMA-expressing metastases appear to be metabolically inactive and 15% of metabolically active metastases lack PSMA expression. Addition of PET with a metabolic tracer, such as 11C-acetate, might be beneficial before making treatment decisions.

Our aim was to compare the effect that having access, versus not having access, to web-based patient information on

Purpose Unexpected focal colonic or rectal radiotracer activity is an usual finding in patients subjected to a PET study. The aim of this work has been to evaluate the clinical significance of this finding in the prediction of an existing colorectal malignancy. Material and methods During the last three years, all patients studied with 18 F-FDG PET/CT and PET for oncologic work-up purposes were prospectively surveyed for focal colorectal radiotracer activity. Colonoscopy was performed in all patients with this incidental finding in order to exclude colonic malignancy. CEA level, maximum standardized uptake value (SUVmax), CT findings, colonoscopy findings and histopathological results were prospectively analyzed in all patients. Results A total of 2290 patients were evaluated, 158 of whom were studied with PET and the remainder with a hybrid PET/CT. Focal FDG colorectal activity was incidentally detected in 27 patients with no previous history of colorectal cancer. Colorectal adenocarcinoma was diagnosed in seven (25.9%) patients. A pre-cancerous lesion was found in eleven patients (40.7%). Eight patients (29.6%) had no macroscopic lesions. One patient was diagnosed with a benign lesion. Any focal activity found in the colon by 18 F-FDG PET/CT examination predicts a probability greater than 50% of an underlying malignant or premalignant lesion in the histopathological analysis (logistic regression, p = 0.01), independently of the calculated SUVmax. Conclusion According to the results of the present study, we recommend the performance of a colonoscopy and biopsy of any suspicious lesions, in all patients with unexpected focal FDG activity found in colon or rectum during a 18 F-FDG PET/CT examination.

The resolution and quantitative accuracy of PET are highly influenced by the reconstruction method. Penalized-likelihood estimation algorithms allow for fully convergent iterative reconstruction, generating a higher image contrast than ordered-subsets expectation maximization (OSEM) while limiting noise. In this study, a type of penalized reconstruction known as block-sequential regularized expectation maximization (BSREM) was compared with time-of-flight OSEM (TOF OSEM). Various strengths of noise penalization factor β were tested along with various acquisition durations and transaxial fields of view (FOVs) with the aim of evaluating the performance and clinical use of BSREM for

Aim A close correlation exists between positron emission tomography (PET)-determined histamine H1-receptor occupancy (H1RO) and the incidence of sedation. Antihistamines with H1RO

Introduccion La disfuncion muscular es una de las manifestaciones sistemicas mas estudiadas en la EPOC. Las alteraciones metabolicas musculares son dificiles de estudiar in vivo, debido a la falta de tecnicas no invasivas. El objetivo fue evaluar sincronicamente la actividad metabolica de diferentes grupos musculares en pacientes con EPOC. Metodos Se incluyeron 39 pacientes y 21 controles (funcion pulmonar normal), candidatos a realizacion de tomografia axial computarizada y por emision de positrones para estadificacion de lesion pulmonar localizada. Tras infusion de 18-fluor-deoxi-glucosa, se captaron imagenes de 2 musculos respiratorios (porciones costal y crural del diafragma, y recto abdominal) y 2 musculos perifericos (cuadriceps y biceps braquial), utilizando como indice de metabolismo glucidico el standard uptake value. Resultados Este indice fue superior en ambas porciones del diafragma comparado con el resto de los musculos en todos los sujetos. Ademas, el diafragma crural y el recto del abdomen mostraban mayor actividad en los pacientes con EPOC que en los controles (1,8 ± 0,7 vs. 1,4 ± 0,8; y 0,78 ± 0,2 vs. 0,58 ± 0,1; respectivamente; p < 0,05). El cuadriceps mostraba una tendencia similar. En los pacientes con EPOC los niveles de captacion de ambos musculos respiratorios y del cuadriceps se correlacionaron directamente con el atrapamiento aereo (r = 0,388; 0,427 y 0,361, respectivamente; p < 0,05). Conclusiones Existe mayor nivel de captacion-utilizacion de glucosa en el diafragma humano respecto de otros musculos en respiracion tranquila. Se confirma cuantitativamente que los pacientes con EPOC tienen incrementado el metabolismo glucidico de sus musculos respiratorios (con tendencia similar para el cuadriceps), en relacion directa con las cargas mecanicas que afrontan.

UNLABELLED: Two mitogen-activated protein kinase kinase (MAPK2, also known as MEK) inhibitors were assessed with (18)F-FDG PET in separate phase I clinical studies, clearly illustrating the potential of metabolic imaging for dose, dosing regimen, and compound selection in early-phase trials and utility for predicting nonresponding patients. METHODS: (18)F-FDG PET data were collected during 2 independent, phase I, dose-escalation trials of 2 novel MEK inhibitors (RO5126766 and RO4987655). PET acquisition procedures were standardized between the 2 trials, and PET images were analyzed centrally. Imaging was performed at baseline; at cycle 1, day 15; and at cycle 3, day 1. A 10-mm-diameter region of interest was defined for up to 5 lesions, and peak standardized uptake values were determined for each lesion. The relationship between PET response and pharmacokinetic factors (dose and exposure), inhibition of extracellular-signal-regulated kinase (ERK) phosphorylation in peripheral blood mononuclear cells, and anatomic tumor response as measured by Response Evaluation Criteria in Solid Tumors was investigated for both compounds. RESULTS: Seventy-six patients underwent PET, and 205 individual PET scans were analyzed. Strong evidence of biologic activity was seen as early as cycle 1, day 15, for both compounds. (18)F-FDG PET revealed striking differences between the 2 MEK inhibitors at their recommended dose for phase II investigation. The mean amplitude of the decrease in (18)F-FDG from baseline to cycle 1, day 15, was greater for patients receiving RO4987655 than for those receiving RO5126766 (47% vs. 16%, respectively; P = 0.052). Furthermore, a more pronounced relationship was seen between the change in (18)F-FDG uptake and dose or exposure and phosphorylated ERK inhibition in peripheral blood mononuclear cells in patients receiving RO4987655. For both investigational drugs, PET responses tended to be greatest in patients with melanoma tumors. (18)F-FDG was able to identify early nonresponding patients with a 97% negative predictive value. CONCLUSION: These data exemplify the role of (18)F-FDG PET for guiding the selection of novel investigational drugs, choosing dose in early-phase clinical development, and predicting nonresponding patients early in treatment.

10549Background: We conducted an open label, single arm phase II clinical trial with irinotecan and cisplatin (I/C) for pediatric patients with glial tumors (EudraCT:2009-010742-59). Methods: Patie...

A 28-year-old man with headache, nausea, and decreased vision had a left parieto-occipital tumor demonstrated by MRI. Postradical resection and histology showed a solid mass containing rhabdoid cells, 10% positive for Ki-67. After completing chemotherapy and radiotherapy treatment, follow-up MRI revealed possible tumoral recurrence. Cerebral F-18 FDG PET revealed no pathologic uptake, and C-11 methionine PET showed a pathologic low uptake. These findings suggested recurrence of a mild-grade aggressiveness tumor, which was confirmed by a second neurosurgical resection.

Thyroid incidentalomas are thyroid lesions encountered during imaging study for nonthyroid diseases [1]. In the general population, the prevalence of thyroid nodules is 4 – 7% through physical exam...

Introduction Muscle dysfunction is one of the most extensively studied manifestations of COPD. Metabolic changes in muscle are difficult to study in vivo, due to the lack of non-invasive techniques. Our aim was to evaluate metabolic activity simultaneously in various muscle groups in COPD patients. Methods Thirty-nine COPD patients and 21 controls with normal lung function, due to undergo computed axial and positron emission tomography for staging of localized lung lesions were included. After administration of 18-fluordeoxyglucose, images of 2 respiratory muscles (costal and crural diaphragm, and rectus abdominus) and 2 peripheral muscles (brachial biceps and quadriceps) were obtained, using the standard uptake value as the glucose metabolism index. Results Standard uptake value was higher in both portions of the diaphragm than in the other muscles of all subjects. Moreover, the crural diaphragm and rectus abdominus showed greater activity in COPD patients than in the controls (1.8±0.7 vs 1.4±0.8; and 0.78±0.2 vs 0.58±0.1; respectively, P

Background: Essential tremor is the most common movement disorder in adults, but its exact etiology and pathophysiology are still not fully understood. There is some consensus, however, about the involvement of the cerebellum and accumulating evidence points towards a dysfunction of the gabaergic system. We hypothesize that the serotonin neurotransmission system may also play a role as it does in tremor in Parkinson disease. This study aimed to investigate the association between the severity of tremor symptoms and the gabaergic and serotoninergic neurotransmission systems in essential tremor. Material and methods: We measured the tremor clinical rating scale score and acquired DASB and Flumazenil PET scans in 10 patients who presented with essential tremor at different stages of clinical severity. Statistically significant correlations were sought between the scale scores and parametric binding potential images. Results: The correlation analysis of cerebellar Flumazenil uptake and tremor clinical rating scale scores reached statistical significance (R2 = 0.423, p = 0.041), whereas no association was detected in the DASB scans. Conclusions: The severity of tremor correlated with the abnormalities found in GABA receptor binding, suggesting a primary gabaergic deficiency or a functional abnormality at the level of GABA(A) receptor subtypes. These results may assist in the rational development of new pharmacological treatments for essential tremor. (C) 2012 Elsevier Ltd. All rights reserved.

A 59-year-old man who presented with weight loss and fatigue showed no pathological findings on the contrastenhanced thorax/abdominal CT scan, but a single frontal nodular lesion on the contrast-enhanced cranial CT scan (a) that was considered to represent a single cerebral metastases from an unknown primary. The F-FDG PET scan was performed for staging to exclude a primary tumour, and also a cerebral-MR scan to complete the diagnostic imaging work-up. The PET/CT scan showed intense FDG uptake (b) by the cerebral lesion, but no evidence of any primary tumour. On the basis of the MR imaging findings, a frontal glioblastoma multiforme, well seen on the T1-weighted image (c), was diagnosed. MR imaging also showed additional multiple small meningeal foci surrounding the cisternal areas. PET/CT also showed heterogeneous FDG uptake at the cervical and dorsal spinal cord on the sagittal view (d), which was more easily detectable by increasing the contrast on the same PET scan sagittal view as multiple foci of FDG uptake distributed along the spinal leptomeningeal area (e, arrows) and also on the PET/CT sagittal fusion image (f, arrows). A spinal MRI study confirmed the leptomeningeal infiltration. Although the frontal lesion was surgically treated, the extensive disease led to the patient’s death within 30 days. Leptomeningeal metastases from previously untreated cerebral glioblastoma spreading through the cerebrospinal fluid is an uncommon diagnostic finding (more commonly detected on necropsy studies) [1]. Although, to date no report of leptomeningeal metastases from glioblastoma detected by F-FDG PET is available in the literature, there are some cases reports of the ability of FDG PET to detect leptomeningeal metastases [2, 3].

In cancer patients, positron emission tomography/ computed tomography (PET/CT) fused images present less variability in target contouring, respect to use only CT images, respectively. However, the gold standard has not yet been clearly established between radiation oncologists with regard to PET images and the methodology of contouring targets with confidence using PET/CT fused images. The aim of this study was to determine whether integrated PET/CT fused images provide advantages in virtual simulation compared with morphological contouring only with CT.Thirty cancer patients were evaluated in an adapted PET/CT hybrid in radiotherapy (RT) setup position, with 20 of them being suitable for RT: 17 were suitable for curative intent, which was the group of interest in this study. All image series were sent to the RT work station (WS) where CT and PET series were automatically fused by Digital Imaging and Communications in Medicine (DICOM) in each case. PET series were threshold and were subjected to source-to-background contrast algorithms to fi nally redefine the original tumour description. Three different radiotherapy plans (RTP) for each patient were compared after targets were contoured: [1] planning over metabolic (PET) contoured targets, [2] planning over only morphologic (CT) targets, and [3] planning over targets obtained for treatment based on fused PET/CT images.PET/CT findings altered initial-stage planning in four patients (23.5%) because they had been undergoing chemotherapy. Gross target volume (GTV) and planning target volume (PTV) based only on PET showed more homogeneity to obtain mean doses (p = 0.025) with respect to those based on PET/CT, respectively. However, no percentage differences were observed in median PTV doses between the planning methods, although there was higher variability in PET/CT planning. Morphological (CT) and PET/ CT target volumes were more voluminous than metabolic (PET) volumes. On the other hand, 20% of metabolic (PET) PTV were out of those defined by PET/CT. Thoracic RT plans based on PET preserved better bilateral lung [percentage volume of lung irradiated with a dose of 20 Gy (V20); significance, R(2) = 0.559, p = 0.006].For our physicians, PET/CT fused images allowed better contouring of primary tumours in 40% of head and neck cancers and 34% of thoracic cancers. PET/CT provides useful information for virtual simulation therapy. Image treatment and planning in an RT workstation is mandatory.

Positron emission tomography (PET) with the glucose analogue [18F] fluoro-2-deoxy-D-glucose ((18)F-FDG-PET) has been used in radiation treatment planning for non-small-cell carcinoma. To date, lymph nodes have been contoured according to the uptake of the tumor. This prospective study was performed to evaluate if nodal volume delineates according to FDG uptake within the primary tumor (PET-GTVnt) is suitable for nodal target volume delineation or if individualized nodal FDG uptake measure (PET-GTVnn) is necessary to better nodal target definition.Forty cases, who underwent a diagnostic (18)F-FDG PET/computed tomography (CT) scan, were included. Two PET-based GTVs for each lymph node were contoured and compared. First, we used an isocontour of 40% of the maximum tumor uptake (PET-GTVnt). Second, an isocontour of 40% of the maximum uptake of each node (PET-GTVnn) was employed. To avoid interobserver variability, this was carried out by the same radiation oncologist. Afterwards, the difference between both lymph node volumes was plotted against the ratio of the maximum uptakes (I(n)/I(t)) in a linear regression analysis.Compared with CT-based lymph node volume (CT-GTVn), the intraclass correlation coefficient of PET-GTVnn was higher than the coefficient of PET-GTVnt (p0.001). All cases could be divided into four groups: undetected (17.5%), detected but overestimated (10%), detected but underestimated (35%), and correctly detected (37.5%).If a method of automatic delineation shall be applied, this method must be applied to every lesion separately. However, to facilitate the delineation in daily practice, when I(n)/I(t) is ≤25%, lymph nodes could be delineated in accordance with tumor uptake, keeping an absolute difference in radii5 mm.

To evaluate the accuracy of carbon 11 (11C) hydroxyephedrine (HED) positron emission tomography (PET) in the detection of pheochromocytomas.Nineteen patients (12 women, seven men; mean age, 53 years) suspected of having pheochromocytoma were evaluated. Patients had enlarged adrenal glands at computed tomography and either increased urinary catecholamine levels (n = 18) or normal biochemistry (n = 1). Dynamic PET examination in the adrenal region was performed after injection of 800 MBq 11C HED. PET data were analyzed visually and semiquantitatively. Time-activity curves were generated for different organs. PET results were validated with histologic evaluation (n = 16) or clinical follow-up (n = 3). The diagnostic value of HED PET was evaluated by calculating the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy.In 12 patients, 13 pheochromocytomas were verified at surgery and histologic evaluation. All but one of the pheochromocytomas were detected with HED PET, which demonstrated elevated uptake. The rest of the patients (n = 7) did not have pheochromocytomas. In these patients, HED PET did not show any abnormal uptake in the suspicious tumors (confirmed at surgery in four patients and at clinical follow-up in three). Mean standardized uptake value of the tumors was 21.4 (range, 11.1-40.9). The time-activity curves for pheochromocytomas showed early uptake after injection, and the activity increased with the time of examination. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of HED PET in the detection of pheochromocytomas were 92% (12 of 13), 100% (seven of seven), 100% (12 of 12), 87.5% (seven of eight), and 95% (19 of 20), respectively.HED PET is useful in the detection of pheochromocytomas, providing a high level of accuracy.

Purpose: To evaluate the utility of FDG-PET in detecting primary tumors in patients with metastatic disease from unknown primary tumors. Methods: 12 patients with metastases from unknown origin after unsuccessful conventional diagnostic procedures were studied. 5 had lymph node metastases (2 axillary, 2 cervical, 1 mediastinal), 3 multiple metastases, 1 in the lung, 1 in the cava vein, 1 in the brain and 1 in adrenal glands. Patients received 400MBq FDG intravenously, and whole body images were acquired 60 min. after injection with an ECAT EXACT HR+. PET results were compared with histological and clinical findings. Results: All but one metastatic lesion was identified by PET. Additional metastases were visualized in 4 patients. In one helped to guide biopsy for histological diagnosis. In 4/11 patients FDG-PET did not reveal lesions suspected to be primary tumor. FDG-PET identified primary tumor in 8/11 patients (breast: 2, pancreas: 2, base of tongue: 1, adrenal gland: 1, lung: 1, stomach: 1). In 4 of them (33% of total) primary tumor was confirmed either histologically or by the clinical evolution (breast: 2, lung: 1, pancreas: 1). In 1 patient FDG-PET was false positive (base of tongue). 3 patients positive FDG-PET have not yet been confirmed. FDG-PET influenced therapeutic procedures in 4 patients (33% of total). 2 underwent surgery (breast), 1 received specific chemotherapy (lung) and 1 palliative chemotherapy (pancreas). Conclusions: Our preliminary results suggest that FDG-PET is a non-invasive technique useful in the detection of unknown primary tumors, can influence in selecting appropriate therapeutic management and could guide biopsies for histologic analysis.

Dear Editor, A 27-year-old man was admitted for evaluation of peripheral lymph nodes with no other systemic symptoms. Initial laboratory tests, peripheral blood smears and bone marrow examinations were unremarkable. The thoracoabdominal computed tomography (CT) scan showed thoracic lymph nodes and a bulky retroperitoneal adenopathic mass. After the lymph node biopsy, the patient was diagnosed with follicular lymphoma grade 3 (World Health Organization) stage 4-A, IPI 1/5, FLIPI 2/5. He received chemotherapy with CHOP–rituximab and local radiotherapy to the abdominal mass. The patient achieved criteria of complete remission uncertain (gallium scintigraphy negative), and he initiated maintenance therapy with rituximab. Three and a half years after, the patient noticed a progressive pain in the left area of the scalp, and he asked for evaluation. On physical examination, he presented a swelling on the left parieto-temporal area of the head that was painful at palpation. A cranial radiography showed an isolated radiolucent lesion on the left parietal zone of the skull. A cranial CT scan described a lytic lesion of 12 mm in diameter in the same area, with edema of subcutaneous tissue. Thoraco-abdominal CT scan and bone marrow biopsy were normal. Bone scintigraphy and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) showed a locally increased uptake of 2×2 cm along the left parietal bone with extension to soft tissue. A surgical biopsy was decided, but a complete resection of the lesion was finally performed. The pathologic appearance of the lesion was a diffuse infiltration by cells with histiocytic appearance, vesicular nuclei, folded and grooved nuclear membranes, inconspicuous nucleoli, and abundant pale eosinophilic cytoplasm. This cluster of cells surrounded a large aggregation of eosinophils with central necrosis. Immunostaining showed cell positivity for CD1a and S-100 antibodies and negativity for CD79a, CD20, CD3, and CD5, and Ki67

BACKGROUND: 18-Fluoro-deoxyglucose positron emission tomography (FDG-PET) is a noninvasive imaging tool for initial staging and evaluation of treatment response in Hodgkin’s lymphoma (HL) and non-Hodgkin’s lymphoma (NHL). PET imaging can provide additional information to conventional imaging as computer tomography (CT). AIM: The aim of this study was to evaluate the role of PET in improving the staging and if this fact could have an impact in prognosis, in compared to CT. METHODS: From February 2005 to January 2008, one hundred ten consecutive patients with NHL (49 aggressive, 32 indolent and 3 unclassifficated) and HL (26 patients) were staged according to the Ann Arbor classification with CT and bone marrow biopsy (BMb). As well, all patients underwent to FDG-PET body before treatment. International Prognostic Index (IPI) was calculated following standard staging (IPI-st) and with standard staging plus FDG-PET (IPI-PET) in NHL. RESULTS: CT and FDG-PET were concordant in 84 patients (66%). In 37 patients (34%) discordance was observed: in 7 patients FDG-PET was negative, in 11 patients FDG-PET detected more bone lesions, in 11 patients FDGPET uptake in other lymph nodes, including spleen infiltration, and in 8 patients FDGPET detected less lymph nodes or organ involvement. However, additional information of FDG-PET changed in staging in 21 out of 37 patients with discordant findings but the IPI risk changed in only 5 patients. Discrepancies CT and FDG-PET were seen in similar proportion in all lymphoma subtypes. Overall survival curves at two years showed no differences between IPI-st and IPI-PET (IPI-st 0–1: 97%, 2–3: 89%, 4–5: 48%; IPI-PET 0–1: 96%, 2–3: 89%, 4–5: 48% ). CONCLUSIONS: FDG-PET can provide additional information to CT in both aggressive or indolent non-Hodgkin lymphoma and Hodgkin lymphoma. CT and FDG-PET were discordant in 30 % of the patients but only half of them showed change of stage. IPI risk was modified in few patients with NHL. Inclusion of patients is ongoing.