Oncological Follow-up with 2-[18F]-FDG PET/CT in Li-Fraumeni Syndrome

Li-Fraumeni syndrome is a rare disorder caused by abnormalities of the tumor-suppressor protein P53 gene. We present the case of a 26-years-old female diagnosed with bilateral ductal carcinoma. The genetic panel for breast cancer gene 1 (BRCA1) and BRCA2 mutations was negative and positive heterozygous germline tumor protein P53 gene mutations, considering Li-Fraumeni syndrome. A 2-[18F]-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) was used for postsurgical staging to show the right lung hypermetabolic nodule. A lobectomy was accomplished, and histopathology reported pulmonary adenocarcinoma. A year later, oncological follow-up was conducted with 2-[18F]-FDG PET/CT without evidence of abnormalities.

18F-FDG-PET-CT: uso racional en el diagnóstico y la estadificación de la enfermedad oncológica / 18F-FDG-PET-CT: rational use in diagnosis and staging of oncologic diseases

Resumen: Las técnicas de imaginología molecular evalúan los procesos metabólicos intracelulares; en la actualidad, son una herramienta eficaz para el diagnóstico oncológico. La técnica más importante y utilizada es la PET-CT (tomografía por emisión de positrones y tomografía computarizada), en la cual, la PET permite obtener una imagen metabólica del tumor, de forma que se determina su viabilidad, mientras que la tomografía computarizada permite la localización anatómica exacta de la lesión. Es así, como la PET-CT es una prueba con un gran desempeño diagnóstico en oncología, permitiendo el diagnóstico temprano, la estadificación y la evaluación de la respuesta a la terapia de pacientes con neoplasias. Este artículo de revisión tiene como objetivo describir las bases técnicas y biológicas de la PET-CT, y su uso racional en oncología, en especial al momento de contribuir en la fase de diagnóstico primario de la neoplasia y en la estadificación de la enfermedad.

Abstract: Molecular imaging techniques evaluate intracellular metabolic processes; currently, these techniques are an effective tool for cancer diagnosis. The most important and widely used technique is PET-CT (positron-emission tomography and computed tomography), wherein PET obtains a metabolic image of the tumor, a way as to determine its viability, while CT enables an accurate anatomical location of the lesion. Hence, PET-CT is a test with high diagnostic performance in oncology, allowing early detection, staging and assessment of response to therapy in patients with malignancies. This review article aims to describe the technical and biological fundamentals of PET-CT, and its rational use in oncologic practice, especially during early detection of cancer and staging of the disease.

Volume-of-interest assessment of oncologic response using 18F-FDG PET/CT: a phantom study.

UNLABELLED: The aim of this study was to evaluate the volume-of-interest (VOI) technique in the measurement of volume radioactivity and in the differentiation of necrotic sites from residual tumor activity in a phantom. METHODS: PET/CT was performed on a phantom filled with (18)F-FDG solution at different concentrations. The VOI was quantified in 2 sessions to evaluate the VOI measurements as a function of activity concentration in the phantom. Software was used to build the VOI, determine the volume radioactivity of the cylindric inserts (cm(3)), and compare them with their real volumes. The VOI technique was also used to discern the mixed distribution of regions of (18)F-FDG activity from cold regions that represent areas of necrosis without tumor activity. RESULTS: Volumes measured with the VOI technique were similar to the actual volumes of cylinders in the phantom (no statistical differences; P > 0.05 after t test analysis). The diameter of cold inserts correlated positively with the percentage of visualization (P < 0.01); in both sessions, it was possible to visualize 100% of the 12.7-, 11.1-, and 9.5-mm cold rods. CONCLUSION: VOI technique has shown great potential for evaluating volume radioactivity and differentiating hot and cold regions in a phantom; clinical studies should be performed with this technique to evaluate its utility.

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

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.

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.

[Musculoskeletal tumor evaluation with 99mTc-Tetrofosmin]. / 99mTc-Tetrofosmin en la evaluación de tumores musculoesqueléticos.

INTRODUCTION: (99m)Tc-tetrofosmin is an efficient agent as a tumor marker. Several studies have proven its efficiency in detection and localization of tumors of the breast, larynx, thyroid, parathyroid glands, lung, brain, skin, lymphatic and musculoskeletal tissues with a sensitivity and specificity of 95% to 100%. It is used as a predictor of therapy efficacy and to localize remaining and recurrent tissue as well as local and distant extension. OBJECTIVE: To determine the sensitivity, specificity and predictive values of the three-phase 99mTc-Tetrofosmin scan in detection of malignant lesions of the musculoskeletal tissue. METHODS: Seventy-three patients of both genders with suspected malignant musculoskeletal lesions were studied by three-phase (vascular, tissue and delayed images) 99mTc-tectrofosmin scans. RESULTS: One-hundred-percent sensitivity, 67.3% specificity, 55% positive predictive value, and 100% negative predictive value. CONCLUSION: Three-phase 99mTc-tectrofosmin scan is useful in detection of malignant lesions of the musculoskeletal system due to its high sensitivity and positive predictive value. Nevertheless, benign pathology such as active inflammation is a source of false positives and the attending physician must consider the aid of complementary studies such as histopathology.

Conceptos actuales en la radiología basada en evidencias: revisión / A review of current concepts in evidence-based radiology

La medicina basada en evidencias (MBE) se fundamenta en un descubrimiento sistemático, evaluación crítica y utilización de la investigación actual publicada en la literatura médica, para la toma de decisiones referentes al cuidado de un paciente individual o políticas de salud. En la radiología (incluyendo sus ramas diagnóstica y terapéutica), los principios y práctica de una MBE han recibido atención limitada. En esta breve revisión, presentamos algunos conceptos básicos de cómo implementar una radiología basada en evidencias y los conceptos y etapas de la MBE y el metaanálisis con enfoque en la radiología basada en evidencias. Se identifican las aplicaciones de ésta en la práctica, la educación y la investigación, y las habilidades requeridas. La aplicación de los principios de la MBE en el diagnóstico por imagen facilita la interpretación de los estudios y sustenta una evaluación bien dirigida. Esta revisión será útil para radiólogos en cualquier etapa de su entrenamiento o desarrollo profesional, con el fin de estimular una práctica radiológica basada en evidencias, especialmente en países en desarrollo.

It has been noted that "Good doctors use both individual clinical expertise and the best available external evidence, and neither alone is enough." Evidence-based medicine (EBM) is defined as the process of systematically finding, critically appraising, and using contemporary research published in the medical literature as a basis to make decisions regarding individual patient care and health care policy. In radiology, including its diagnostic and interventional aspects, the principles and practice of EBM have not been thoroughly studied. In this brief review article, we describe key aspects of evidence-based radiology (EBR), concepts and steps followed in EBM and meta-analysis. The skills required to practice EBR are identified, and the roles of EBR in radiologic practice, education, and research are discussed. The application of EBM principles to diagnostic imaging facilitates the interpretation of imaging studies and produces a sound and comprehensive radiologic evaluation. This review could be useful for radiologists and clinicians at any stage of their training or career. It encourages the practice of EBM and EBR especially in developing countries.

[A review of current concepts in evidence-based radiology]. / Conceptos actuales en la radiología basada en evidencias. Revisión.

It has been noted that "Good doctors use both individual clinical expertise and the best available external evidence, and neither alone is enough. " Evidence-based medicine (EBM) is defined as the process of systematically finding, critically appraising, and using contemporary research published in the medical literature as a basis to make decisions regarding individual patient care and health care policy. In radiology, including its diagnostic and interventional aspects, the principles and practice of EBM have not been thoroughly studied. In this brief review article, we describe key aspects of evidence-based radiology (EBR), concepts and steps followed in EBM and meta-analysis. The skills required to practice EBR are identified, and the roles of EBR in radiologic practice, education, and research are discussed. The application of EBM principles to diagnostic imaging facilitates the interpretation of imaging studies and produces a sound and comprehensive radiologic evaluation. This review could be useful for radiologists and clinicians at any stage of their training or career. It encourages the practice of EBM and EBR especially in developing countries.