The differential diagnosis between chondroma and intraosseous chondrosarcoma is based on imaging and clinical exams, but only a biopsy can confirm diagnosis. The aim of this study was to evaluate the value of PET–CT in differentially diagnosing chondroma and chondrosarcoma. From October 2009 to May 2015, 36 patients with cartilaginous bone lesions in the extremities, 12 (33.3 %) men and 24 (66.6 %) women, were prospectively included in the study. Patients ranged in age from 21 to 68 years, with a mean age of 44 years. Lesions were located in the long bones: in the proximal humerus in 26 (72.2 %) patients, in the femoral shaft in 1 (2.7 %), in the distal femur in 7 (19.4 %), and in the proximal tibia in 2 (5.5 %). The SUVmax value of 2.0 was used to separate between patients submitted to surgery and patients submitted to observation. Among the 36 patients studied, 17 (47.2 %) had SUVmax ≤ 2.0, and they were diagnosed as chondroma and they were treated conservatively. Follow-up ranged from 14 to 76 months, averaging 38 months. Nineteen (52.7 %) patients with SUVmax >2.0 were diagnosed as chondrosarcoma and underwent surgery. The area of the curve, calculated considering the SUV variable as numeric, is estimated in 0.966, with a 95 % confidence interval from 0.906 to 1.000. To evaluate the sensitivity, specificity and positive/negative predictive values, it was built a 2 × 2 table. Significance was set at p < 0.05. According the criteria of maximum sensitivity and specificity, the cut point suggested to SUVmax was 2.2. If we consider this point, it is possible to identify 19 of 36 positive cases to chondroma (52.8 %), it means, all chondrosarcomas of the series. We concluded that PET–CT can be used as an objective and quantitative method of differentiating between chondromas and chondrosarcomas located within the long bones. It represents a complementary examination to standard imaging (X-ray, scintigraphy, CT and MRI) and pathological exams. The SUVmax between 2.0 and 2.2 would be a range area between chondroma and chondrosarcoma and this range can be of value, among others exams, in decide the best treatment for patients with cartilaginous lesions in long bones.Level of evidence Level I—diagnostic study—prospectively investigating a diagnostic test using a universally applied “gold” standard.

Rationale:This is the report of the first case of TAFRO syndrome (Thrombocytopenia, Anasarca, myelofibrosis, Renal dysfunction, Organomegaly) in Latin America.Patient concerns:The patient was a 61-year-old white woman of Ashkenazi Jewish descent, who presented with a history of 8 days of nausea, vomiting, and fever; severe pitting edema in both legs, ascites, splenomegaly, and palpable axillary lymph nodes.Diagnoses:Abdominal computed tomography (CT) showed bilateral pleural effusion and retroperitoneal lymph node enlargement.Interventions:Anasarca and worsening of renal function led to admission to the intensive care unit (ICU) with multiple organ failure, requiring mechanical ventilation, vasopressor medications, and continuous renal replacement therapy (CRRT). Diagnosis of TAFRO syndrome was made on day 18 after admission, based on clinical findings and results of bone marrow and lymph node biopsies. She was treated with methylprednisolone, tocilizumab, and rituximab. One week after the first tocilizumab dose, she had dramatic improvements in respiratory and hemodynamic status, and was weaned from ventilator support and vasopressor medications.Outcomes:After 2 weeks of therapy, CRRT was switched to intermittent hemodialysis. On day 46, the patient was discharged from the ICU to the general ward, and 3 months after admission, she went home.Lessons:Provided the interleukin-6 measurement is available, this approach is suggested in cases of TAFRO syndrome, in order to customize the treatment.

Background: The positron emission tomography (PET) ligand 68 Ga-Glu-urea-Lys(Ahx)-HBED-CC (68 Ga-PSMA-11) targets the prostate-specific membrane antigen (PSMA), upregulated in prostate cancer cells. Although 68 Ga-PSMA-11 PET is widely used in research and clinical practice, full kinetic modeling has not yet been reported nor have simplified methods for quantification been validated. The aims of our study were to quantify 68 Ga-PSMA-11 uptake in primary prostate cancer patients using compartmental modeling with arterial blood sampling and to validate the use of standardized uptake values (SUV) and image-derived blood for quantification. Results: Fifteen patients with histologically proven primary prostate cancer underwent a 60-min dynamic 68 Ga-PSMA-11 PET scan of the pelvis with axial T1 Dixon, T2, and diffusion-weighted magnetic resonance (MR) images acquired simultaneously. Time-activity curves were derived from volumes of interest in lesions, normal prostate, and muscle, and mean SUV calculated. In total, 18 positive lesions were identified on both PET and MR. Arterial blood activity was measured by automatic arterial blood sampling and manual blood samples were collected for plasmato-blood ratio correction and for metabolite analysis. The analysis showed that 68 Ga-PSMA-11 was stable in vivo. Based on the Akaike information criterion, 68 Ga-PSMA-11 kinetics were best described by an irreversible two-tissue compartment model. The rate constants K 1 and k 3 and the net influx rate constants K i were all significantly higher in lesions compared to normal tissue (p < 0.05). K i derived using image-derived blood from an MR-guided method showed excellent agreement with K i derived using arterial blood sampling (intraclass correlation coefficient = 0.99). SUV correlated significantly with K i with the strongest correlation of scan time-window 30-45 min (rho 0.95, p < 0.001). Both K i and SUV correlated significantly with serum prostate specific antigen (PSA) level and PSA density. Conclusions: 68 Ga-PSMA-11 kinetics can be described by an irreversible two-tissue compartment model. An MR-guided method for image-derived blood provides a non-invasive alternative to blood sampling for kinetic modeling studies. SUV showed strong correlation with K i and can be used in routine clinical settings to quantify 68 Ga-PSMA-11 uptake.

In recent years, medical imaging with hybrid techniques has widely accepted and employed in clinical routine. PET/MRI offers significant advantages, including excellent contrast and resolution and reduced ionizing radiation, as compared to well-established PET/CT. Therefore, PET/MRI is a promising modality for oncologic imaging of some regions, such as brain, head and neck, liver and pelvis. This article set out to analyze clinical conditions that could benefit from PET/MRI imaging based on our caseload. The potential of PET/MRI to become the imaging modality of choice for assessment of neurologic and oncologic conditions associated with soft tissues is highlighted. Clinical aspects of PET/MRI and its application to clinical cases are illustrated with examples extracted from the authors’ preliminary experience.

The hippocampus is one of the earliest sites involved in the pathology of Alzheimer's disease (AD). Therefore, we specifically investigated the sensitivity and specificity of hippocampal volume and glucose metabolism in patients being evaluated for AD, using automated quantitative tools (NeuroQuant – magnetic resonance imaging [MRI] and Scenium – positron emission tomography [PET]) and clinical evaluation.This retrospective study included adult patients over the age of 45 years with suspected AD, who had undergone fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET-CT) and MRI. FDG-PET-CT images were analyzed both qualitatively and quantitatively. In quantitative volumetric MRI analysis, the percentage of the total intracranial volume of each brain region, as well as the total hippocampal volume, were considered in comparison to an age-adjusted percentile. The remaining brain regions were compared between groups according to the final diagnosis.Thirty-eight patients were included in this study. After a mean follow-up period of 23 ± 11 months, the final diagnosis for 16 patients was AD or high-risk mild cognitive impairment (MCI). Out of the 16 patients, 8 patients were women, and the average age of all patients was 69.38 ± 10.98 years. Among the remaining 22 patients enrolled in the study, 14 were women, and the average age was 67.50 ± 11.60 years; a diagnosis of AD was initially excluded, but the patients may have low-risk MCI. Qualitative FDG-PET-CT analysis showed greater accuracy (0.87), sensitivity (0.76), and negative predictive value (0.77), when compared to quantitative PET analysis, hippocampal MRI volumetry, and specificity. The positive predictive value of FDG-PET-CT was similar to the MRI value.The performance of FDG-PET-CT qualitative analysis was significantly more effective compared to MRI volumetry. At least in part, this observation could corroborate the sequential hypothesis of AD pathophysiology, which posits that functional changes (synaptic dysfunction) precede structural changes (atrophy).

SUVmax from PET/CT and PET/MR are linearly correlated, on average 20% higher on PET/CT than on PET/MR and should, therefore, not be used interchangeably in patient follow-up.

The authors report the case of a 70-year-old male patient with chronic lymphoid leukemia who presented subsequently a papillary carcinoma of the thyroid with metastases to regional lymph nodes. The patient was treated with surgical thyroidectomy with regional and cervical lymph node excision and radioiodine therapy (I-131). The protocolar control scintigraphy 4 days after the radioactive dose showed I-131 uptake in both axillae and even in the inguinal regions. PET/CT showed faint FDG-F-18 uptake in one lymph node of the left axilla. An ultrasound guided fine needle biopsy of this lymph node identified by I-131 SPECT/CT and FDG-F-18 PET/CT revealed lymphoma cells and was negative for thyroid tissue and thyroglobulin content. The sequential blood counts done routinely after radiation treatment showed a marked fall until return to normal values of leucocytes and lymphocytes (absolute and relative), which were still normal in the last control 19 months after the radioiodine administration. Chest computed tomography showed a decrease in size of axillary and paraaortic lymph nodes. By immunohistochemistry, cells of the lymphoid B lineage decreased from 52% before radioiodine therapy to 5% after the procedure. The authors speculate about a possible sodium iodide symporter expression by the cells of this lymphoma, similar to some other non-thyroid tumors, such as breast cancer cells.

288 ResumoObjetivo: Avaliar se diferentes parâmetros de análise da linfocintilografia permitem a distinção entre membros com e sem linfedema em pacientes com quadro clínico de edema unilateral.Métodos: Levantamento retrospectivo dos exames de 20 pacientes submetidos a linfocintilografia para investigação de edema unilateral de membros inferiores, divididos em pacientes com linfedema primário (grupo 1, n = 7) ou secundário pós-traumático (grupo 2, n = 13). Foi realizada linfocintilografia após injeção subdérmica de soroalbumina humana marcada com tecnécio-99m nos pés, com imagens da região inguinal durante 15 min e imagens dos membros inferiores após 15 min e 1 h. Os parâmetros analisados foram: tempo de aparecimento da cadeia inguinal, índice semiquantitativo (fluxo linfático, difusão intersticial, aspecto dos vasos, tempo de aparecimento e aspecto dos linfonodos inguinais) e inclinação da curva de atividade em função do tempo da região inguinal. As medidas nos membros clinicamente acometidos foram comparadas aos membros sem linfedema em ambos os grupos.Resultado: O tempo médio de aparecimento da cadeia inguinal e o índice semiquantitativo foram significativamente maiores nos membros com linfedema que nos membros sem linfedema quando considerados todos os pacientes, com maior retardo e índice semiquantitativo nos membros com linfedema do grupo 1 em relação aos do grupo 2.Conclusão: A análise do tempo de aparecimento da cadeia inguinal e o índice semiquantitativo fornecem parâmetros objetivos de avaliação do linfedema que podem auxiliar na detecção e seguimento dos pacientes com linfedema.Palavras-chave: Cintilografia, linfedema. AbstractObjective: To evaluate whether different parameters could be used in the analysis of lymphoscintigraphy to distinguish affected from unaffected limbs in patients with unilateral edema.Methods: Twenty patients who underwent lymphoscintigraphy for screening of unilateral lower limb edema were retrospectively assessed and divided into patients with primary lymphedema (group 1, n = 7) or secondary post-traumatic edema (group 2, n = 13). Technetium 99m-labeled human serum albumin was subdermally administered in the feet, followed by a dynamic lymphoscintigraphy of the pelvis during 15 min and static images of the lower limbs after 15 min and 1 h. Analyzed parameters were detection time of groin activity, semi-quantitative index (lymph flow, interstitial diffusion, aspect of vessels, detection time and aspect of inguinal lymph nodes) and slope of groin time-activity curve. The parameters of clinically affected limbs were compared to those of the contralateral limbs in both groups.Results: Detection time of groin activity and semi-quantitative index were significantly higher in affected limbs considering all patients, with a more severe delay and a higher semi-quantitative index in group 1 compared to group 2.Conclusion: Analysis of detection time of groin activity and semiquantitative index can add objective parameters that can be used in the diagnosis and follow-up of patients with ly...