The utility of 18F-FDG-PET/CT in detecting extracranial large vessel vasculitis in rheumatic polymyalgia or giant cell arteritis. A systematic review and meta-analysis.

OBJECTIVE: Systematic review of current evidence to analyze the prevalence of extracranial large vessel vasculitis (LVV) using 18F-FDG PET/CT in patients with polymyalgia rheumatica (PMR) or giant cell arteritis (GCA). MATERIALS AND METHODS: PubMed and EMBASE were searched and the results were screened by two reviewers. Study quality was assessed using a modified version of the Newcastle-Ottawa scale. Heterogeneity between studies was assessed using the I2 statistic and the Q test. Further subgroup analyses were performed by disease type, study quality, and 18F-FDG PET/CT uptake criteria. Publication bias was assessed by funnel plot and Egger's test. RESULTS: 268 publications were identified, of which 17 met the selection criteria and were included in the meta-analysis. The overall pooled prevalence of extracranial LVV by 18F-FDG PET/CT was 54.5% [95% CI: 42.6%-66.1%]. In patients with GCA the prevalence was significantly higher than in patients with PMR (60.1% vs. 41.8%, P = 0.006). Likewise, studies with a lower risk of bias reported a higher prevalence of extracranial LVV (61.1% vs. 46.9%; P = 0.010). No publication bias was observed. CONCLUSIONS: The 18F-FDG PET/CT test may be useful in the detection of extracranial LVV, both in patients with PMR or GCA. Such involvement is more frequent in patients with GCA, and may vary depending on the quality of the studies.

Comparison of prognostic value of different metabolic response criteria determined by PET/CT in patients with metastatic breast cancer under CDK 4/6 inhibitor treatment.

PURPOSE: This study evaluates the prognostic role of different [18F]FDG PET/CT metabolic response criteria in metastatic breast cancer (MBC) patients treated with cyclin-dependent kinase 4/6 inhibitors (CDK 4/6). MATERIALS AND METHODS: We retrospectively evaluated the data of MBC patients treated with CDK 4/6 inhibitors who underwent an [18F]FDG PET/CT scan before starting and during treatment. [18F]FDG PET/CT response was assessed with the European Organization for Research and Treatment of Cancer (EORTC), PET Response Criteria in Solid Tumors (PERCIST), and whole-body total lesion glycolysis (WBTLG) criteria. Fleiss kappa was computed to assess the agreement between metabolic response criteria. The endpoint of the study was progression-free survival (PFS). PFS data were analyzed by the Kaplan-Meier method and compared using the log-rank test. RESULTS: The study included sixteen MBC patients who received CDK 4/6 inhibitors therapy. According to PERCIST, partial metabolic response (PMR) was found in seven patients, stable metabolic disease (SMD) in seven patients, and progressive metabolic disease (PMD) in two patients. According to EORTC, PMR was detected in eight patients, SMD in seven patients, and PMD in one patient. According to WBTLG, PMR was found in 10 patients, SMD in four patients, and PMD in two patients. There was a fair agreement between the three criteria. While progression was detected in seven of the patients during follow-up, no progression was detected in nine of them. Kaplan-Meier analysis revealed that the responders according to WBTLG showed significantly longer PFS than non-responders. CONCLUSION: Treatment response according to WBTLG criteria during treatment appears to be associated with prolonged PFS in patients treated with CDK 4/6 inhibitors for MBC.

Prevalence and clinical significance in our setting of incidental uptake in the thyroid gland found on 18F-fluordeoxyglucose positron emission tomography-computed tomography (PET-CT).

INTRODUCTION: The expanding use of 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) has resulted in an increased frequency of incidentally discovered areas of FDG uptake within the thyroid gland. In these incidentalomas, high malignancy rates are reported. The study aimed, on the one hand, to determine the prevalence in our setting of thyroid incidentalomas in patients with no previous history of thyroid cancer undergoing an FDG PET-CT as well as the risk of malignancy and, on the other hand, to evaluate the usefulness of the maximum standard uptake value (SUVmax) for detecting thyroid cancer. MATERIAL AND METHODS: The FDG PET-CT scans performed at our hospital between June 2013 and December 2020 were retrospectively reviewed. In those incidentalomas with sufficient additional investigation, a diagnosis of benign or malignant was established based on the complementary tests. RESULTS: From the 21,594 PET-CT scans performed, 398 (1.8%) patients had an incidental FDG uptake, either focal (n=324) or diffuse (n=74). Among incidentalomas with further investigation, the rate of malignancy was higher in patients with focal FDG uptake than in those with diffuse uptake (26.5% versus 4%, respectively, p<0.05). The SUVmax value was significantly lower in benign focal lesions (5.7 [range: 2.3-66] than in malignant ones 10.6 [range: 3.1-51.2]; p<0.05). Nearly a quarter of malignant diagnoses (23.3%) were related to potentially aggressive tumours. CONCLUSION: The high rate of malignant tumours found among PET-CT incidentalomas and the high proportion of aggressive tumours demonstrate the need for a standardised approach in the investigation of incidental focal FDG uptake in the thyroid gland.

Adenoma hepatocelular con captación de 18 flúor deoxiglucosa en PET-TC SCAN. Una "mini-review" e informe de un nuevo caso / 18-fluoro-deoxyglucose uptake on PET-CT in hepatocellular adenoma. A mini review with a new case Report

RESUMEN La captación de 18 FDG en PET-TC por un adenoma hepatocelular (HCA) es poco frecuente. Esta situación genera dudas en cuanto a los diagnósticos diferenciales y tratamiento. El objetivo de este artículo fue realizar una mini revisión de los últimos 37 años de HCA con avidez por el 18FDG y presentar un nuevo caso. Sobre la base de un estudio realizado por otros autores entre 1984 y 2014, se amplía la búsqueda utilizando las mismas palabras clave hasta el año 2021. Se analizan los datos relevantes. Entre 1984 y 2021 detectamos 38 casos en 37 años. Fue más frecuente en mujeres en edad reproductiva. Los subtipos H-HCA e I-HCA fueron los más frecuentes. El tratamiento quirúrgico fue el más empleado. La diferenciación celular y los trastornos metabólicos de la glucosa y de los lípidos favorecerían la captación de 18FDG. La resección hepática ofrecería mayores garantías permitiendo el estudio completo de la lesión.

ABSTRACT Hepatocellular adenoma (HCA) uptake of 18FDG uptake on PET-CT is rare. This situation poses doubts about the differential diagnoses and treatment. The aim of this article is to perform a mini review of 18FDG avid HCA over the past 37 years and to describe a new case presentation. Based on a study conducted by other authors between 1984 and 2014, we extended the search until 2021 using the same keywords. The relevant data were analyzed. Between 1984 and 2021 we detected 38 cases in 37 years. HCAs were more common in women of childbearing age. The most common types were H-HCA an I-HCA. Surgical resection was the treatment most used. Cell differentiation and glucose and lipid metabolic diseases would favor 18FDG uptake. Liver resection provides better outcomes, allowing for a complete examination of the lesion.

Association of 18F-FDG PET/CT textural features with immunohistochemical characteristics in invasive ductal breast cancer / Asociación de características texturales de PET/TC 18F-FDG con características inmunohistoquímicas en el cáncer de mama ductal invasivo

Objetivo: Este estudio investiga si las características de textura (TF) extraídas de la tomografía por emisión de positrones/tomografía computarizada (PET/TC) con fluoruro-18 fluorodesoxiglucosa (F-18 FDG) están asociadas con las características inmunohistoquímicas (IHC) del carcinoma ductal de mama invasivo (IDBC).Materiales y métodos: Se evaluó la relación de TF con IHC [receptor de estrógeno (ER), receptor de progesterona (PR), receptor 2 del factor de crecimiento epidérmico humano (HER-2), índice de proliferación Ki-67 y grados histológicos] de tumores primarios extirpados únicamente para una evaluación más precisa. Por lo tanto, los pacientes con IDBC en estadio temprano que se sometieron a una exploración por PET/TC con F-18 FDG pre-operatoria para la estadificación se incluyeron en este estudio retrospectivo. La estadificación clínica se realizó de acuerdo con la 8a edición del American Joint Committee on Cancer. El valor máximo de captación estandarizada (SUVmáx) y 37 TF del tumor primario se extrajeron de F-18 FDG PET/TC. Se utilizó la prueba de correlación de rango de Spearman para evaluar la correlación entre TF y SUVmáx. Se generaron curvas de características operativas del receptor para definir el rendimiento diagnóstico de cada parámetro. Entre estos parámetros, aquellos con mayor rendimiento diagnóstico se incluyeron en el modelo de regresión logística multivariante para identificar los predictores independientes de las características histopatológicas.Resultados: Se incluyeron un total de 124 pacientes. La uniformidad del histograma, la energía GLCM y la homogeneidad GLCM mostraron una fuerte correlación negativa con SUVmax, mientras que GLRLM-SRHGE, GLZLM-HGZE, GLRLM-HGRE, GLCM-entropía, GLCM-contraste, histograma-entropía y GLCM-disimilitud mostraron una fuerte correlación positiva. Algunos de los TF se asociaron de forma independiente con ER-negatividad, PR-negatividad, HER-2-positividad y aumento del índice

Objectıves: This study investigates whether textural features (TFs) extracted from 18F-FDG positron emission tomography/computed tomography (PET/CT) are associated with immunohistochemical characteristics (IHCs) of invasive ductal breast carcinoma (IDBC).Materials and methods: The relationship of TFs with IHCs [estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2), Ki-67 proliferation index, and histological grades] from solely excised primary tumors were evaluated for a more accurate assessment. Therefore patients with early-stage IDBC who underwent pre-operative 18F-FDG PET/CT scan for staging were included in this retrospective study. The clinical staging was performed according to the 8th edition of the American Joint Committee on Cancer. Maximum standardized uptake value (SUVmax) and 37TFs of the primary tumor were extracted from 18F-FDG PET/CT. Spearman’s rank correlation test was used to evaluate the correlation between TFs and SUVmax. Receiver operating characteristic curves were generated to define the diagnostic performance of each parameter. Among these parameters, those with the highest diagnostic performance were included in the multivariate logistic regression model to identify the independent predictors of histopathological characteristics.Results: A total of 124 patients were included. Histogram-uniformity, grey-level co-occurrence matrix (GLCM), GLCM-energy, and GLCM-homogeneity showed a strong negative correlation with SUVmax, while grey-level run-length matrix (GLRLM), GLRLM-SRHGE, grey-level zone length matrix (GLZLM), GLZLM-HGZE, GLRLM-HGRE, GLCM-entropy, GLCM-contrast, histogram-entropy, and GLCM-dissimilarity showed a strong positive correlation. Some of the TFs were independently associated with ER-negativity, PR-negativity, HER-2-positivity, and increased Ki-67 proliferation index (GLCM-contrast, GLZLM-GLNU, histogram-uniformity, and shape-sphericity respectively)

Association of 18F-FDG PET/CT textural features with immunohistochemical characteristics in invasive ductal breast cancer.

OBJECTiVES: This study investigates whether textural features (TFs) extracted from 18F-FDG positron emission tomography/computed tomography (PET/CT) are associated with immunohistochemical characteristics (IHCs) of invasive ductal breast carcinoma (IDBC). MATERIALS AND METHODS: The relationship of TFs with IHCs [estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2), Ki-67 proliferation index, and histological grades] from solely excised primary tumors were evaluated for a more accurate assessment. Therefore patients with early-stage IDBC who underwent pre-operative 18F-FDG PET/CT scan for staging were included in this retrospective study. The clinical staging was performed according to the 8th edition of the American Joint Committee on Cancer. Maximum standardized uptake value (SUVmax) and 37TFs of the primary tumor were extracted from 18F-FDG PET/CT. Spearman's rank correlation test was used to evaluate the correlation between TFs and SUVmax. Receiver operating characteristic curves were generated to define the diagnostic performance of each parameter. Among these parameters, those with the highest diagnostic performance were included in the multivariate logistic regression model to identify the independent predictors of histopathological characteristics. RESULTS: A total of 124 patients were included. Histogram-uniformity, grey-level co-occurrence matrix (GLCM), GLCM-energy, and GLCM-homogeneity showed a strong negative correlation with SUVmax, while grey-level run-length matrix (GLRLM), GLRLM-SRHGE, grey-level zone length matrix (GLZLM), GLZLM-HGZE, GLRLM-HGRE, GLCM-entropy, GLCM-contrast, histogram-entropy, and GLCM-dissimilarity showed a strong positive correlation. Some of the TFs were independently associated with ER-negativity, PR-negativity, HER-2-positivity, and increased Ki-67 proliferation index (GLCM-contrast, GLZLM-GLNU, histogram-uniformity, and shape-sphericity respectively). While SUVmax had an independent association with high-grade and triple-negativity, GLZLM-SZLGE, a high-order TF that shows the distribution of the short homogeneous zones with low grey-levels, had an independent association with axillary lymph node metastasis. CONCLUSIONS: ER-negative, PR-negative, HER-2-positive, triple-negative, high-grade, highly proliferative, and high-stage tumors were found to be more glycolytic and metabolically heterogeneous. These findings suggest that the use of TFs in addition to SUVmax may improve the prognostic value of 18F-FDG PET/CT in IDBC, as certain TFs were independently associated with many IHCs and predicted axillary lymph node involvement.

Association of 18F-FDG PET/CT textural features with immunohistochemical characteristics in invasive ductal breast cancer. / Asociación de características de textura de la PET/TC con [18F]FDG con las características inmunohistoquímicas en el cáncer de mama ductal infiltrante.

OBJECTiVES: This study investigates whether textural features (TFs) extracted from F-18 FDG positron emission tomography/computed tomography (PET/CT) are associated with IHCs of invasive ductal breast carcinoma (IDBC). MATERIALS AND METHODS: The relationship of TFs with IHCs [estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2), Ki-67 proliferation index, and histological grades] from solely excised primary tumors were evaluated for a more accurate assessment. Therefore patients with early-stage IDBC who underwent pre-operative F-18 FDG PET/CT scan for staging were included in this retrospective study. The clinical staging was performed according to the 8th edition of the American Joint Committee on Cancer. Maximum standardized uptake value (SUVmax) and 37 TFs of the primary tumor were extracted from F-18 FDG PET/CT. Spearman's rank correlation test was used to evaluate the correlation between TFs and SUVmax. Receiver operating characteristic curves were generated to define the diagnostic performance of each parameter. Among these parameters, those with the highest diagnostic performance were included in the multivariate logistic regression model to identify the independent predictors of histopathological characteristics. RESULTS: A total of 124 patients were included. Histogram-uniformity, GLCM-energy, and GLCM-homogeneity showed a strong negative correlation with SUVmax, while GLRLM-SRHGE, GLZLM-HGZE, GLRLM-HGRE, GLCM-entropy, GLCM-contrast, histogram-entropy, and GLCM-dissimilarity showed a strong positive correlation. Some of the TFs were independently associated with ER-negativity, PR-negativity, HER-2-positivity, and increased Ki-67 proliferation index (GLCM-contrast, GLZLM-GLNU, histogram-uniformity, and shape-sphericity respectively). While SUVmax had an independent association with high-grade and triple-negativity, GLZLM-SZLGE, a high-order TF that shows the distribution of the short homogeneous zones with low grey-levels, had an independent association with axillary lymph node metastasis. CONCLUSIONS: ER-negative, PR-negative, HER-2-positive, triple-negative, high-grade, highly proliferative, and high-stage tumors were found to be more glycolytic and metabolically heterogeneous. These findings suggest that the use of TFs in addition to SUVmax may improve the prognostic value of F-18 FDG PET/CT in IDBC, as certain TFs were independently associated with many IHCs and predicted axillary lymph node involvement.

Classic fever of unknown origin: analysis of a cohort of 87 patients according to the definition with qualitative study criterion. / Fiebre de origen desconocido clásica: análisis de una cohorte de 87 pacientes según la definición con criterio de estudio cualitativo.

OBJECTIVES: The aim of this study was to evaluate the characteristics of fever of unknown origin (FUO) according to the definition with qualitative study criterion and of patients without diagnosis. MATERIALS AND METHODS: Prospective observational study performed from 2009 to 2017 of all patients who were diagnosed with FUO according to the extended definition with qualitative study criterion. Demographic, clinical, diagnostic and evolving variables were evaluated. RESULTS: Of the 87 patients registered, 17.3% presented criteria of inflammation of unknown origin (IUO). The diagnoses were: non-infectious inflammatory diseases (NIID) in 19 patients (21.8%), infections in 15 (17.2%), miscellaneous in 14 (16.1%), malignant diseases in 13 (15%) and without diagnosis in 26 (29.9%). In 17.6% of the cases, a potentially diagnostic clue (PDC) was identified. The patients without diagnosis were characterized by a lower number of total PDC (5.9±3.3 vs. 8.7±3.4; P=.000), fewer clinical signs (.4±.6 vs. .9±.8; P=.001), a smaller number of tests in the previous study (2.7±2.1 vs. 4.6±2; P=.000), a shorter diagnostic interval (14.6±7.7 days vs. 21.4±9.5 days; P=.029) and less alteration of erythrocyte sedimentation rate (52.3±41.3mm/h vs. 89.8±42.7mm/h; P=.000), haemoglobin (12.9±1.7g/dl vs. 11.7±1.6g/dl; P=.003) and albumin (36.9±6.4g/l vs. 33.2±7.2g/l; P=.025). 18F-fluorodeoxyglucose positron-emission tomography combined with computed tomography (18F-FDG-PET/TC) proved to be helpful in 37% of the cases. Mortality was 6.8%. CONCLUSIONS: The definition of FUO with qualitative study criterion incorporates a diagnostic protocol that provides clear benefits in terms of cost-effectiveness.

False positive in fluorodeoxyglucose-F18 positron emission tomography computed tomography scan of inferior vena cava leiomyoma in patient with a suspected paraganglioma. / Falso positivo en estudio de tomografía de emisión de positrones con fluorodesoxiglucosa-F18 de un leiomioma de vena cava inferior en paciente con sospecha de paraganglioma.

Leiomyomas are benign tumors derived from smooth muscle tissue that rarely present outside the uterus. These tumors do not usually show FDG uptake. We present the case of a patient with hypertension refractory to treatment and a lesion arising from inferior vena cava, that shows intense FDG uptake in PET/CT scan, suggestive of paraganglioma, with a final histological diagnosis of leiomyoma.

PET/CT 18F-FDG en carcinomatosis peritoneal: revisión de la fisiopatología y presentación de dos casos / PET/CT 18F-FDG in peritoneal carcinomatosis: A review of the pathophysiology and a presentation of two cases

Resumen La carcinomatosis peritoneal corresponde a la diseminación o extensión en la cavidad peritoneal de un cáncer originado en algún órgano o viscera del abdomen, generalmente asociado a tumores digestivos o ginecológicos. También puede presentarse en forma primaria en patologías como el mesotelioma y el adenocarcinoma primario peritoneal. Las imágenes anatómicas son el pilar de la evaluación de las siembras peritoneales, pero pequeños implantes neoplásicos pueden ser difíciles de detectar con TAC o resonancia magnética. El PET/CT 18F-FDG tiene el poder de mejorar la detección de las metástasis peritoneales. Está indicado en pacientes con marcadores tumorales elevados, con imágenes anatómicas negativas o no conclusivas y en pacientes seleccionados para citorreducción completa. Se suma a las imágenes convencionales en la detección y estadificación de la carcinomatosis peritoneal, y es una herramienta diagnóstica útil en el monitoreo de la respuesta a la terapia y en el seguimiento a largo plazo.

Abstract Peritoneal carcinomatosis is the dissemination or extension in the peritoneal cavity of a cancer originated in some organ or abdominal viscera, generally associated with digestive or gynaecological neoplasms. It can also occur in primary form, as in mesothelioma and primary peritoneal adenocarcinoma. Anatomical images are essential for the evaluation of peritoneal seeding, but small neoplastic implants can be difficult to detect with CT or MR imaging. PET/CT 18F-FDG can improve the detection of peritoneal metastases. It is indicated in patients with elevated tumour markers, with negative or inconclusive anatomical images, and in patients selected for complete debulking. PET/CT 18F-FDG adds to conventional images in the detection and staging of peritoneal carcinomatosis, and is a useful diagnostic tool in monitoring the response to therapy and in long-term follow-up.

SEOM-SERAM-SEMNIM guidelines on the use of functional and molecular imaging techniques in advanced non-small-cell lung cancer. / Guía SEOM-SERAM-SEMNIM sobre el empleo de las técnicas de imagen funcional y molecular en el cáncer de pulmón no microcítico avanzado.

Imaging in oncology is an essential tool for patient management but its potential is being profoundly underutilized. Each of the techniques used in the diagnostic process also conveys functional information that can be relevant in treatment decision making. New imaging algorithms and techniques enhance our knowledge about the phenotype of the tumor and its potential response to different therapies. Functional imaging can be defined as the one that provides information beyond the purely morphological data, and include all the techniques that make it possible to measure specific physiological functions of the tumor, whereas molecular imaging would include techniques that allow us to measure metabolic changes. Functional and molecular techniques included in this document are based on multi-detector computed tomography (CT), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), magnetic resonance imaging (MRI), and hybrid equipments, integrating PET with CT (PET/CT) or MRI (PET-MRI). Lung cancer is one of the most frequent and deadly tumors although survival is increasing thanks to advances in diagnostic methods and new treatments. This increased survival poises challenges in terms of proper follow-up and definitions of response and progression, as exemplified by immune therapy-related pseudoprogression. In this consensus document, the use of functional and molecular imaging techniques will be addressed to exploit their current potential and explore future applications in the diagnosis, evaluation of response and detection of recurrence of advanced NSCLC.

Adrenal tuberculosis masquerading as disseminated malignancy: A pitfall of (18)F-FDG PET/CT Imaging.

Non-invasive characterization of adrenal lesions is a commonly encountered diagnostic challenge. Characteristic clinical and correlative imaging findings may assist in only arriving at a probable diagnosis. Currently, (18)F-FDG PET/CT is considered to provide the most comprehensive imaging information. We here present a case of bilateral adrenal tuberculosis that highlights the need for caution during the interpretation of (18)F-FDG PET/CT and also the need to suggest histopathological correlation.

[Use of 18F-FDG-positron emission tomography in presurgical evaluation of nonspecific or suspectious adrenal masses in non-oncologic patients]. / Utilidad de la tomografía de emisión de positrones con 18F-fluorodesoxiglucosa en la evaluación prequirúrgica de masas adrenales con características radiológicas inespecíficas o sospechosas de malignidad en pacientes sin cáncer.

BACKGROUND AND OBJECTIVE: Our purpose was to assess the utility of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in pre-surgical characterization of adrenal masses. These masses were incidentally discovered in non-oncologic patients or during the study of endocrine hormone overproduction. These nodular lesions showed nonspecific or suspicious radiological features in the imaging tests routinely performed (CT and/or MRI). PATIENTS AND METHODS: This is a cross-sectional and prospective study in 12 patients with adrenal masses which were radiologically non-specific or suspicious for malignancy before adrenalectomy. An 18F-FDG-PET was made and quantitative FDG uptake (SUVmax) in the adrenal region (adrenal SUVmax) and liver (liver SUVmax), and the ratio SUVmax adrenal/liver was calculated. These parameters were related to the pathological findings. We evaluated the accuracy of the test by receive operating curves (ROC). RESULTS: The ROC to discriminate between benign and malignant lesions showed that the SUVmax was a better parameter than size or SUVmax adrenal/liver ratio. Using a SUVmax cutoff value≥3.1, sensitivity, specificity, positive and negative predictive value of the test were 100, 67, 50 and 100%, while a SUVmax adrenal/liver ratio≥1.8 showed a sensitivity, specificity, positive and negative predictive value of 67, 100, 100 and 90%, respectively. The presence of a SUVmax adrenal/liver ratio≥1.8 showed a statistically significant association with carcinoma occurrence. CONCLUSION: 18F-FDG-PET may be useful in the characterization of nonspecific or suspicious adrenal masses discovered in patients without a previous history of cancer. Its use in some cases could avoid unnecessary interventions.

Diagnosis by (18)F-FDG PET/CT of infective endocarditis, staging and monitoring of antibiotic treatment after transposition of surgically corrected great arteries.

Infective endocarditis is one of the leading causes of fever of unknown origin in those patients with intravascular catheters, prosthetic valves or cardiovascular implantable electronic devices. The diagnosis of infective endocarditis is made according to modified Duke criteria, which are based on blood culture and echocardiographic findings. Demonstration of vegetation with the transoesophageal echocardiography may be difficult in these cases with previous anatomical changes, especially in early phases. Positron emission tomography with (18)F-fluorodeoxyglucose ((18)F-FDG PET/CT) is well known to show an increased glucidic metabolism in malignant, inflammatory, and infectious processes. Thus, it provides useful functional imaging that enables the disease causing the fever of unknown origin to be detected well before structural changes are evident. Moreover, (18)F-FDG PET/CT helps to detect infectious extra-cardiac involvement, since the whole body is imaged with this technique. (18)F-FDG PET/CT may have an additional promising role for the monitoring of response to antimicrobial therapy in patients with established infective endocarditis, thus evaluating standard treatment outcome, as well as evaluating the need for alternative/intensified treatment options.

[Study of patients with prolonged fever with (18)F-FDG PET/CT]. / Estudio de pacientes con síndrome febril prolongado con 18F-FDG PET-TC.

OBJECTIVE: To review the findings on (18)F-FDG PET-CT in patients with fever of unknown origin lasting more than 7 days. MATERIAL AND METHODS: This retrospective descriptive observational study included 93 (18)F-FDG PET-CT studies to detect a fever-causing focus done at three nuclear medicine centers from October 2006 through February 2014. A nuclear medicine specialist and a radiologist reviewed the images for foci of pathological uptake; another specialist's opinion resolved discrepancies. The findings on (18)F-FDG PET-CT studies were checked against clinical and/or histological findings. RESULTS: Abnormal (18)F-FDG uptake on PET-CT that could explain the cause of the fever was found in 52 (56%) of the 93 studies, and the cause of the fever was confirmed in 50 of these 52 studies. In the 50 cases in which the cause of the fever was confirmed, infection was the most common cause (54%), followed by noninfectious inflammatory disease (28%) and tumors (18%). CONCLUSION: (18)F-FDG PET-CT is useful in diagnosing the cause of prolonged febrile illness, so it might be practical to use it earlier in the diagnostic process.

[Usefulness of (18)FDG PET-CT scan as a diagnostic tool of fever of unknown origin]. / Utilidad de la tomografía por emisión de positrones con (18)F-Fluorodesoxiglucosa combinada con tomografía computarizada en la orientación diagnóstica de la fiebre de origen desconocido.

BACKGROUND AND OBJECTIVE: Classic fever of unknown origin (FUO) is defined as the presence of fever greater than 38.3°C of at least 3 weeks with an uncertain diagnosis. Identification of the etiology is crucial in guiding further diagnostic procedures and subsequent patient management. The aim of this study was to evaluate the role of fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography combined with computed tomography (PET/CT) in the diagnostic orientation of FUO. MATERIAL AND METHOD: An observational retrospective study was performed, including 30 consecutive patients who had been studied between March 2010 and September 2013. Twenty-six out of 30 patients (86.67%) had a definitive diagnosis after pathologic confirmation in 15 cases, microbiological findings in one patient and clinical and radiological follow-up in 10 patients (mean: 16.38 months). RESULTS: Among the positive scans, malignancy (n=10), inflammatory (n=8), infectious (n=4) and miscellaneous causes (n=1) were identified. (18)F-FDG PET/CT had a diagnostic accuracy of 90.00%, sensitivity of 88.46% (95% confidence interval [95% CI] 76-101), specificity of 100.00% (95% CI 100-100), positive predictive values of 100.00% (95% CI100-100) and negative predictive value of 57.14% (95% CI 20-91). CONCLUSIONS: (18)F-FDG PET/CT provided useful for the etiologic diagnosis of FUO, with high sensitivity and specificity. (18)F-FDG PET/CT has an incremental morphological and functional value, especially indicating the best biopsy site.

Optimización del uso de las imágenes en la patología suprarrenal (parte 1) / Optimization of the use of imaging in adrenal pathology (part 1)

Objetivos de aprendizaje: El objetivo de este trabajo es proponer un algoritmo de estudio por imágenes de las lesiones suprarrenales que permita arribar a un diagnóstico correcto en el menor tiempo posible. Esto favorece la adopción de la conducta terapéutica más apropiada para cada patología y puede modificar en forma sustancial un tratamiento. Aunque las características estructurales de las lesiones generalmente son inespecíficas, es posible, a través de las técnicas de imágenes actuales, diferenciar las lesiones compatibles con procesos benignos de las compatibles con procesos malignos y, con la colaboración del endocrinólogo y el laboratorio, también se pueden distinguir las lesiones funcionantes de las no funcionantes. Revisión de tema: Se evaluaron en forma retrospectiva, entre mayo del 2009 y diciembre del 2011, 157 pacientes con patología suprarrenal. En total, eran 95 mujeres y 61 hombres, de 33 a 78 años (media: 55 años). El protocolo de estudio consistió en una tomografía computada (TC) sin contraste intravenoso (IV), con toma de la densidad de la lesión, seguida de una tomografía computada con contraste intravenoso y tiempo de lavado con toma de densidad de la lesión en tiempo portal y tardío a los 15 minutos (tiempo de lavado o wash-out). Las mediciones y cálculos realizados fueron: tamaño de la lesión suprarrenal, densidad media de la misma durante las tres fases estudiadas y porcentajes de lavado relativo y absoluto. Se realizó resonancia magnética (RM) y tomografía computada por emisión de positrones con 18F-fluorodesoxiglucosa (FDG-PET/TC) sólo en aquellos pacientes que así lo requirieron. Además, se compararon los resultados con los de la literatura actualizada sobre el tema. Hallazgos en imágenes: La conjunción de los datos clínicos, de laboratorio y las imágenes con el algoritmo propuesto permitió identificar 59 adenomas no funcionantes (49 unilaterales y 10 bilaterales), 29 adenomas funcionantes, 9 hiperplasias bilaterales, 4...

Objectives of training: The aim of this study is to propose an algorithm for the evaluation of adrenal lesions in order to arrive at the correct diagnosis in the shortest possible time.This method would favor the most appropriate therapeutic procedures for each pathology and may substantially modifi ed a given treatment. In spite of the fact that the structural features of lesions are generally non-specifi c, it is possible with imaging techniques, to establish compatible features which could help us differentiate benign from malignant lesions and with the contribution of the endocrinologist and the laboratory, to distinguish functional from non-functional ones.Topic revision: A retrospective evaluation was carried out from May 2009 to December 2011 on 157 patients with adrenal diseases, including 95 females and 61 males, from 33 to 78 years of age (mean age 55). The study protocol consisted of non-contrasted intravenous computed tomography, with lesion density measurement, followed by contrasted intravenous computed tomography and wash out time with lesion density determination in portal time and later at 15’ during wash out.Measurements and calculations were: adrenal lesion size, medium density and absolute and relative washing percentiles. Magnetic resonance and 18F-fl uorodesoxyglucose positron emission tomography was only performed on those patients who required these techniques. A comparison of the present results with those in the literature is included.Imaging fi ndings: Fifty-nine patients with non-functional adenoma were identifi ed (49 unilateral and 10 bilateral), 29 functional adenomas, 9 with bilateral hyperplasia, 4 myelolipomas (2 in a female patient with simple virilizing congenital adrenal hyperplasia), 2 cysts, 2 hematomas, 3 lymphomas (2 secondary and 1 primary bilateral), 30 metastases, 5 adrenocortical carcinomas, 12 pheochromocytomas,1 malignant pheochromocytoma, and 1 ganglioneuroma...

Optimización del uso de las imágenes en la patología suprarrenal (parte 1) / Optimization of the use of imaging in adrenal pathology (part 1)

Objetivos de aprendizaje: El objetivo de este trabajo es proponer un algoritmo de estudio por imágenes de las lesiones suprarrenales que permita arribar a un diagnóstico correcto en el menor tiempo posible. Esto favorece la adopción de la conducta terapéutica más apropiada para cada patología y puede modificar en forma sustancial un tratamiento. Aunque las características estructurales de las lesiones generalmente son inespecíficas, es posible, a través de las técnicas de imágenes actuales, diferenciar las lesiones compatibles con procesos benignos de las compatibles con procesos malignos y, con la colaboración del endocrinólogo y el laboratorio, también se pueden distinguir las lesiones funcionantes de las no funcionantes. Revisión de tema: Se evaluaron en forma retrospectiva, entre mayo del 2009 y diciembre del 2011, 157 pacientes con patología suprarrenal. En total, eran 95 mujeres y 61 hombres, de 33 a 78 años (media: 55 años). El protocolo de estudio consistió en una tomografía computada (TC) sin contraste intravenoso (IV), con toma de la densidad de la lesión, seguida de una tomografía computada con contraste intravenoso y tiempo de lavado con toma de densidad de la lesión en tiempo portal y tardío a los 15 minutos (tiempo de lavado o wash-out). Las mediciones y cálculos realizados fueron: tamaño de la lesión suprarrenal, densidad media de la misma durante las tres fases estudiadas y porcentajes de lavado relativo y absoluto. Se realizó resonancia magnética (RM) y tomografía computada por emisión de positrones con 18F-fluorodesoxiglucosa (FDG-PET/TC) sólo en aquellos pacientes que así lo requirieron. Además, se compararon los resultados con los de la literatura actualizada sobre el tema. Hallazgos en imágenes: La conjunción de los datos clínicos, de laboratorio y las imágenes con el algoritmo propuesto permitió identificar 59 adenomas no funcionantes (49 unilaterales y 10 bilaterales), 29 adenomas funcionantes, 9 hiperplasias bilaterales, 4 mielolipomas (2 de ellos en una paciente con hiperplasia suprarrenal congénita virilizante simple), 2 quistes, 2 hematomas, 3 linfomas (2 secundarios y 1 primario bilateral), 30 metástasis, 5 carcinomas adrenocorticales, 12 feocromocitomas, 1 feocromocitoma maligno y 1 ganglioneuroma. Conclusión: La utilización de un algoritmo de estudio adecuado, con las herramientas diagnósticas más apropiadas y accesibles, permite la correcta caracterización de las lesiones suprarrenales. A su vez, evita la pérdida de tiempo, el diagnóstico incorrecto, la irradiación excesiva del paciente y la mala utilización de los recursos.(AU)

Objectives of training: The aim of this study is to propose an algorithm for the evaluation of adrenal lesions in order to arrive at the correct diagnosis in the shortest possible time. This method would favor the most appropriate therapeutic procedures for each pathology and may substantially modifi ed a given treatment. In spite of the fact that the structural features of lesions are generally non-specifi c, it is possible with imaging techniques, to establish compatible features which could help us differentiate benign from malignant lesions and with the contribution of the endocrinologist and the laboratory, to distinguish functional from non-functional ones. Topic revision: A retrospective evaluation was carried out from May 2009 to December 2011 on 157 patients with adrenal diseases, including 95 females and 61 males, from 33 to 78 years of age (mean age 55). The study protocol consisted of non-contrasted intravenous computed tomography, with lesion density measurement, followed by contrasted intravenous computed tomography and wash out time with lesion density determination in portal time and later at 15’ during wash out. Measurements and calculations were: adrenal lesion size, medium density and absolute and relative washing percentiles. Magnetic resonance and 18F-fl uorodesoxyglucose positron emission tomography was only performed on those patients who required these techniques. A comparison of the present results with those in the literature is included. Imaging fi ndings: Fifty-nine patients with non-functional adenoma were identifi ed (49 unilateral and 10 bilateral), 29 functional adenomas, 9 with bilateral hyperplasia, 4 myelolipomas (2 in a female patient with simple virilizing congenital adrenal hyperplasia), 2 cysts, 2 hematomas, 3 lymphomas (2 secondary and 1 primary bilateral), 30 metastases, 5 adrenocortical carcinomas, 12 pheochromocytomas,1 malignant pheochromocytoma, and 1 ganglioneuroma. Conclusion: The use of an appropriate study algorithm, with proper diagnostic tools, allows the correct characterization of adrenal lesions. Moreover, this approach prevents loss of time, a wrong diagnosis, excessive irradiation of the patient, and incorrect use of resources.(AU)

Conceptos básicos del 18F-FDG PET/CT: definición y variantes normales / Basic concepts on 18F-FDG PET/CT: definitions and normal variants

La tomografía por emisión de positrones con tomografía multicorte (PET/CT) constituye uno de los métodos de diagnóstico por imagen más modernos; esta tecnología llegó a nuestro país en los tres últimos años. Aunque los principios físicos del PET datan de hace más de 30 años, la fusión de las imágenes con la tomografía multicorte en el posprocesamiento, ha marcado un hito en la detección de estructuras anatómicas con una captación anormal de radiofármacos que puede estar relacionada con inflamación o neoplasia. Este artículo presenta una revisión breve de los principios básicos de PET/CT, la física de la generación de un radiofármaco, la adquisición de la imagen, y sobre todo, se muestran ejemplos de las “variantes normales” que presentan una captación aumentada de 18F-FDG, y que no están relacionadas a un proceso neoplásico.

The PET/CT (positron emission tomography with multislice helical computed tomography), is nowadays one of the leader imaging diagnostic tools in medicine. This technology has been present in Mexico since the last three years. Although the physical principles of PET has been known for more than 30 years, it has been the introduction of PET/CT what let the acquisition and post processing of fused PET/CT images currently used in imaging diagnosis in clinical medicine. These fused PET/CT images allow an accurate localization of the abnormal fluorine-18 Fluorodeoxyglucose (18F-FDG) uptake, which can be related to inflammation or neoplastic processes. This article presents a brief review of the fundamentals of PET/CT, the basic physics principles and examples of normal variants of the 18F-FDG uptake that are not associated with a neoplastic entity.