Controversy in the initial nodal staging of rectal cancer (MRI or PET/CT?).

OBJECTIVE: To compare the usefulness of MRI and PET/CT in nodal staging (N) of patients with locally advanced rectal cancer (LARC). MATERIAL AND METHODS: Retrospective study of patients with LARC, who completed their initial staging with PET/CT, between January-20 and March-23. Regional nodes were assessed, and N was determined using both techniques according to TNM criteria. Concordance between MRI and PET/CT was analyzed. The accuracy of both techniques was calculated for those patients who underwent direct surgery. Non-regional pelvic lymph nodes were evaluated by both modalities. RESULTS: Among the 73 patients, 48 were ultimately diagnosed with a locally advanced stage. Of these, 39 underwent neoadjuvant treatment (chemoradiotherapy) followed by surgery, and 9 direct surgery. In 25, the PET/CT extension study revealed distant disease, leading to systemic treatment. Weak concordance was observed between MRI and PET/CT in determining N (k=0.286; p<0.005). Out of 73 patients, 31(42%) exhibited concordance, and 42(58%) showed discordance. In 83% of the discordant cases, MRI overstaged compared to PET/CT, with 17 cases indicating nodal involvement (N+) by MRI and N0 by PET/CT. Diagnostic accuracy was 78% for both techniques. Sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 75%, 80%, and 75% for MRI, and 60%, 100%, 100%, and 67%, for PET/CT. PET/CT identified pelvic metastatic adenopathies in 8 patients that were not visible/doubtful by MRI. CONCLUSIONS: In the initial nodal staging of rectal cancer MRI overstages relative to PET/CT. Both modalities are complementary, PET/CT offers higher specificity and MRI higher sensitivity.

Desenmascarando la polimialgia reumática, papel de la Medicina Nuclear / Decoding polymyalgia rheumatica, the role of Nuclear Medicine Imaging

La polimialgia reumática (PMR) es una enfermedad inflamatoria de las articulaciones que se presenta en pacientes mayores de 50 años con dolor y rigidez matutina prolongada en las cinturas del hombro y la cadera y en el cuello. La falta de hallazgos clínicos específicos, signos de laboratorio, biomarcadores y métodos de imagen establecidos dificulta el diagnóstico de los pacientes con esta enfermedad. La 18F-FDG PET/TC es una técnica de imagen funcional que constituye una herramienta consolidada en Oncología y que también ha demostrado su utilidad en el campo de las enfermedades inflamatorias. El objetivo de este trabajo es presentar evidencia bibliográfica sobre el uso de métodos de imagen molecular como la PET/TC para el diagnóstico precoz, la evaluación de la actividad de la enfermedad y la respuesta terapéutica en la PMR. Al mismo tiempo, se consideran las ventajas, las desventajas y las contraindicaciones de otros métodos (AU)

Polymyalgia rheumatica (PMR) is an inflammatory joint disease that presents in patients older than 50 years with prolonged morning pain and stiffness in the shoulder and hip joints and neck. The lack of specific clinical findings, laboratory signs, biomarkers and established imaging methods makes it difficult to diagnose patients with this disease. 18F-FDG PET/CT is a functional imaging technique that is an established tool in oncology and has also proven useful in the field of inflammatory diseases. The aim of this paper is to present literature evidence on the use of molecular imaging methods such as PET/CT for early diagnosis, assessment of disease activity and therapeutic response in PMR. At the same time, the advantages, disadvantages and contraindications of other methods are considered (AU)

Utility of applying a diagnostic algorithm in giant cell arteritis based on the level of clinical suspicion. / Utilidad de la aplicación de un algoritmo diagnóstico en la arteritis de células gigantes en función del grado de sospecha clínica.

INTRODUCTION: To reach the diagnosis of giant cell arteritis (GCA), signs, symptoms, laboratory tests, imaging findings, and occasionally anatomopathological results from temporal artery biopsy are evaluated. This study describes the results of an algorithm analysis based on clinical and ultrasound evaluation of patients with suspected GCA, highlighting its diagnostic utility by contrasting its use in different clinical suspicion scenarios. METHOD: Prospective multicenter study evaluating patients referred with suspected GCA through a preferential circuit (fast track), grouping them according to low or high clinical suspicion of GCA. Each of these scenarios is evaluated by biopsy and ultrasound for all patients, resulting in positive, indeterminate, or negative outcomes, yielding six possible groups. Potential areas of improvement are explored, emphasizing that, following a negative or indeterminate ultrasound, 18-FDG-PET-CT could be recommended. We analyze the results and application of a diagnostic algorithm, confirming its efficiency and applicability based on whether there is high or low clinical suspicion. RESULTS: Sixty-nine patients (41 in the high suspicion group and 28 in the low suspicion group). There were 41 new diagnoses of GCA: 35 in the high suspicion group and 6 in the low suspicion group. Using ultrasound alone, the initial algorithm has an overall diagnostic efficiency of 72.5%, which improves to 80.5% when including 18F-FDG-PET/CT. The negative predictive value of ultrasound in patients with low clinical suspicion is 84.6%, and the positive predictive value of ultrasound in patients with high suspicion is 100%, improving sensitivity from 57.1% to 80.8% with 18F-FDG-PET/CT in this scenario. Temporal artery biopsy was performed on all patients, with no differences in sensitivity or specificity compared to ultrasound. In cases where all three tests - ultrasound, biopsy, and 18F-FDG-PET/CT - are performed, sensitivity increases to 92.3% in patients with high clinical suspicion. CONCLUSION: In situations of high clinical suspicion, the algorithm provides sufficient information for the diagnosis of GCA if ultrasound is positive. A negative ultrasound is sufficient to rule out the diagnosis in the context of low clinical suspicion. 18-FDG-PET-CT may be useful in patients with high suspicion and negative or indeterminate ultrasound results.

Decoding polymyalgia rheumatica, the role of Nuclear Medicine Imaging.

Polymyalgia rheumatica (PMR) is an inflammatory joint disease that presents in patients older than 50 years with prolonged morning pain and stiffness in the shoulder and hip joints and neck. The lack of specific clinical findings, laboratory signs, biomarkers and established imaging methods makes it difficult to diagnose patients with this disease. 18F-FDG PET/CT is a functional imaging technique that is an established tool in oncology and has also proven useful in the field of inflammatory diseases. The aim of this paper is to present literature evidence on the use of molecular imaging methods such as PET/CT for early diagnosis, assessment of disease activity and therapeutic response in PMR. At the same time, the advantages, disadvantages and contraindications of other methods are considered.

Contribución de la medicina nuclear en la cirugía de precisión en el cáncer de mama / Nuclear medicine contribution to precision surgery in breast cancer

La medicina nuclear ha contribuido significativamente en la cirugía de precisión en el cáncer de mama en las últimas décadas. La cirugía radioguiada (CRG) ha permitido la biopsia del ganglio centinela (GC) en la evaluación de la infiltración ganglionar regional modificando el manejo de pacientes con cáncer de mama precoz. Para la axila, el procedimiento de la biopsia del GC ha significado un decremento de complicaciones y una mejor calidad de vida en comparación con la disección de los ganglios linfáticos axilares. Originalmente, la biopsia del GC se indicó principalmente en tumores cT1-2, sin evidencia de metástasis en los ganglios linfáticos axilares. Sin embargo, en los últimos años la biopsia del GC también se está ofreciendo a pacientes con tumores grandes o multifocales, carcinoma ductal in situ, recidiva del cáncer de mama ipsilateral y a pacientes que reciben tratamiento sistémico neoadyuvante (TSN) para cirugía conservadora de mama. Paralelamente a esta evolución, varias asociaciones científicas están tratando de homogeneizar cuestiones como la elección del radiotrazador, el lugar de inyección de la mama, la estandarización de las imágenes preoperatorias y el momento de la biopsia del GC en relación con el TSN, así como el manejo de las metástasis no axilares del GC (p. ej., cadena mamaria interna). Además, la CRG se usa actualmente para lograr la extirpación de tumores de mama primarios mediante inyección intralesional de radiocoloides o mediante implantación de semillas de yodo radiactivo que también se emplean para marcar los ganglios linfáticos axilares metastásicos. Este último procedimiento contribuye a manejar la axila con ganglios positivos en combinación con la PET/TC con [18F]FDG en un esfuerzo por adaptar el tratamiento sistémico y locorregional (AU)

Nuclear medicine has significantly contributed to precision surgery in breast cancer in the past decades. Radioguided surgery (RGS) has enabled sentinel node (SN) biopsy in assessing regional nodal involvement modifying the management of patients with early breast cancer. For the axilla the SN procedure has resulted in fewer complications and better quality of life when compared with axillary lymph node dissection. Originally, SN biopsy principally concerned cT1-2 tumors without evidence of axillary lymph node metastases. However, in last years SN biopsy is also being offered to patients with large or multifocal tumors, ductal carcinoma in situ, ipsilateral breast cancer relapse, and to patients receiving neoadjuvant systemic treatment (NST) for breast sparing surgery. Parallel to this evolution various scientific associations are trying to homogenise issues such as radiotracer choice, breast injection site, preoperative imaging standardisation and SN biopsy timing in relation to NST as well as management of non-axillary SN metastasis (e.g. internal mammary chain). Additionally, RGS is currently used to accomplish primary breast tumour excision either by intralesional radiocolloid injection or by radioactive iodine seed implantation which is also employed to target metastatic axillary lymph nodes. This latter procedure contributes to manage the node-positive axilla in combination with 18F-FDG PET/CT in an effort to tailor systemic and loco regional treatment (AU)

Heterogeneidad del tumor primario en la18F-FDG PET/TC pretratamiento para predecir el pronóstico en pacientes con cáncer de recto sometidos a cirugía tras terapia neoadyuvante / Primary tumor heterogeneity on pretreatment18F-FDG PET/CT to predict outcome in patients with rectal cancer who underwent surgery after neoadjuvant therapy

Objetivo Estudio retrospectivo cuyo objetivo fue investigar el valor de las características de textura de los tumores primarios en la PET/TC con 18F-FDG pretratamiento para la predicción de la respuesta al tratamiento, la progresión y la supervivencia global en pacientes con cáncer de recto que se sometieron a cirugía después de la terapia neoadyuvante (TNA). Métodos Se incluyeron en este estudio pacientes con cáncer de recto que se sometieron a estudio PET/TC con 18F-FDG antes del tratamiento y se sometieron a cirugía después de TNA. Se registraron las características clínico-patológicas, la fecha del último seguimiento, la evolución y fallecimiento. Los parámetros de las texturas y los convencionales de PET (Standard Uptake Value-SUVmax, volumen tumoral metabólico-MTV, glucólisis total de la lesión-TLG) se obtuvieron a partir de imágenes PET/TC utilizando el programa LifeX. Los parámetros se agruparon utilizando el índice de Youden en el análisis ROC. Los factores que predicen la respuesta patológica al tratamiento, la progresión y la supervivencia global se determinaron mediante regresión logística y análisis de regresión de Cox. Resultados Cuarenta y cuatro pacientes (26-59% hombres, 18-41% mujeres; 60,1 ± 11,4 años) con cáncer de recto fueron incluidos en este estudio. El número de pacientes respondedores y no respondedores a TNA fueron de 15 (34,9%) y 28 (65,1%), respectivamente. La mediana de la duración del seguimiento fue de 29,9 meses. 9 (20,5%) mostraron progresión de la enfermedad y 8 (18,2%) fallecieron durante el período de seguimiento. Los parámetros de entropía GLCM de diferencia y correlación GLCM se encontraron como predictores independientes para la respuesta a TNA. Los parámetros de positividad del margen quirúrgico, rango intercuartílico de intensidad CONV y textura AUC-CSHDISC fueron predictores independientes de progresión (AU)

Purpose This retrospective study aimed to investigate the value of texture features of primary tumors in pretreatment18F-FDG PET/CT in the prediction of response to treatment, progression, and overall survival in patients with rectal cancer who underwent surgery after neoadjuvant therapy (NAT). Method Patients with rectal cancer who had pretreatment18F-FDG PET/CT, and underwent surgery after NAT were included in this study. Clinicopathologic features, date of last follow-up, progression, and death were recorded. Textural and conventional PET parameters (maximum standardized uptake value-SUVmax, metabolic tumor volume-MTV, total lesion glycolysis-TLG) were obtained from PET/CT images using LifeX program. Parameters were grouped using Youden index in ROC analysis. Factors predicting the pathological response to treatment, progression, and overall survival were determined using logistic regression and Cox regression analyses. Results Forty-four patients (26(59%) male, 18 (41%) female; 60.1 ± 11.4 years) with rectal cancer were included in this study. The numbers of patients with responders and non-responders to NAT were15(34.9%) and 28(65.1%), respectively. One patient’ pathology report did not contain the response status to NAT. The median of follow-up duration was 29.9 months. 9(20.5%) showed disease progression, and 8(18.2%) died during the follow-up period. Difference entropy GLCM and correlation GLCM parameters were found as independent predictors for response to NAT. The positivity of surgical margin, intensity interquartile range CONV and AUC-CSHDISC texture parameters were independent predictors of progression, while normalized inverse difference GLCM and LZLGEGLZLM parameters were independent predictorsof mortality. Conclusion The texture parameters obtained from pretreatment18F-FDG PET/CT have presented a more robust predictive value than conventional parameters in patients with rectal cancer who underwent surgery after NAT (AU)

Evaluación de la supervivencia de los pacientes con cáncer de recto metastásico mediante parámetros radiómicos y volumétricos de la PET/TC con [18F]FDG de estadificación / Evaluation of the survival of patients with metastatic rectal cancer by staging [18F]FDG PET/CT radiomic and volumetric parameters

Objetivo El objetivo de este estudio es predecir el pronóstico de pacientes con cáncer de recto metastásico (CRM) mediante la obtención de un modelo con algoritmos de aprendizaje automático (AA) a través de datos volumétricos y radiómicos obtenidos de la PET/TC basal. Métodos Pacientes con CRM que se sometieron a imágenes PET/TC con [18F]FDG para estadificación en nuestro hospital entre enero 2015 y enero de 2021 se evaluaron mediante el software LIFEx. El volumen de interés (VOI) del tumor primario fue generado. Además, se evaluaron los valores del volumen metabólico tumoral total (tMTV) y la glucólisis de lesión total (TLG) de los focos tumorales en todo el cuerpo. Se evaluaron los datos clínicos y radiómicos con algoritmos de AA para crear un modelo que predijera la supervivencia. Se investigaron asociaciones significativas entre estas características y la supervivencia a 1 y 2 años. Resultados El algoritmo de bosque aleatorizado fue el algoritmo más exitoso para predecir la supervivencia a 2 años (AUC: 0,843; PRC: 0,822 y CCM: 0,583). Los valores de tMTV y tTLG tuvieron éxito en la predicción de la supervivencia a un año (p 0,002 y 0,007, respectivamente). Conclusiones Además del importante papel de la PET/TC con [18F]FDG en la estadificación de pacientes con CRM, este estudio muestra que es posible predecir la supervivencia con métodos de AA, con parámetros obtenidos mediante el análisis de textura a partir del tumor primario y parámetros volumétricos de todo el cuerpo (AU)

Objective The aim of this study was to predict the prognosis in patients with metastatic rectal cancer (mRC) by obtaining a model with machine learning (ML) algorithms through volumetric and radiomic data obtained from baseline 18-Fluorine Fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) images. Methods Sixty-two patients with mRC who underwent [18F]FDG PET/CT imaging for staging between January 2015 and January 2021 were evaluated using LIFEx software. The volume of interest (VOI) of the primary tumor was generated and volumetric and textural features were obtained from this VOI. In addition, the total metabolic tumor volume (tMTV) and total lesion glycolysis (TLG) values of tumor foci in the whole body were evaluated. Clinical and radiomic data were evaluated with ML algorithms to create a model that predicts survival. Significant associations between these features and 1- and 2-year survival were investigated. Results The random forest algorithm was the most successful in predicting 2-year survival (AUC: 0.843, precision-recall curve: 0.822 and Matthew's correlation coefficient: 0.583). The model obtained with this algorithm was able to predict 49 patients with 79.03% accuracy. While tMTV and TLG values were successful in predicting 1-year survival (p: 0.002 and 0.007, respectively), texture characteristics of the primary tumor did not show a significant relationship with 1-year survival. Conclusions In addition to the important role of [18F]FDG PET/CT in staging patients with mRC, this study shows that it is possible to predict survival with ML methods, with parameters obtained using texture analysis of the primary tumor and whole body volumetric parameters (AU)

Primary tumor heterogeneity on pretreatment 18F-FDG PET/CT to predict outcome in patients with rectal cancer who underwent surgery after neoadjuvant therapy.

PURPOSE: This retrospective study aimed to investigate the value of texture features of primary tumors in pretreatment 18F-FDG PET/CT in the prediction of response to treatment, progression, and overall survival in patients with rectal cancer who underwent surgery after neoadjuvant therapy(NAT). METHODS: Patients with rectal cancer who had pretreatment 18F-FDG PET/CT, and underwent surgery after NAT were included in this study. Clinicopathologic features, date of last follow-up, progression, and death were recorded. Textural and conventional PET parameters(maximum standardized uptake value-SUVmax, metabolic tumor volume-MTV, total lesion glycolysis-TLG) were obtained from PET/CT images using LifeX program. Parameters were grouped using Youden index in ROC analysis. Factors predicting the pathological response to treatment, progression, and overall survival were determined using logistic regression and Cox regression analyses. RESULTS: Forty-four patients (26(59%) male, 18(41%) female; 60.1±11.4 years) with rectal cancer were included in this study. The numbers of patients with responders and non-responders to NAT were 15(34.9%) and 28(65.1%), respectively. One patient' pathology report did not contain the response status to NAT. The median of follow-up duration was 29.9 months. 9(20.5%) showed disease progression, and 8(18.2%) died during the follow-up period. Difference entropyGLCM and correlationGLCM parameters were found as independent predictors for response to NAT. The positivity of surgical margin, intensity interquartile rangeCONV and AUC-CSHDISC texture parameters were independent predictors of progression, while normalized inverse differenceGLCM and LZLGEGLZLM parameters were independent predictors of mortality. CONCLUSION: The texture parameters obtained from pretreatment 18F-FDG PET/CT have presented a more robust predictive value than conventional parameters in patients with rectal cancer who underwent surgery after NAT.

Impact of 18F-FDG-PET/CT on the management of Staphylococcus aureus bacteraemia: A retrospective observational study / Impacto de la 18F-FDG-PET/TC en el manejo de la bacteriemia por Staphylococcus aureus: resultados de un estudio retrospectivo observacional

Objectives: To assess the impact of 18F-FDG-PET/CT on the diagnosis and management of patients with Staphylococcus aureus bacteraemia (SAB). Methods: Post hoc analysis of a prospective cohort of consecutive adult patients diagnosed with SAB (January 2013–December 2017). Patients who underwent 18F-FDG-PET/CT at the discretion of the attending physician were included. Endpoints were the identification of previously unknown infectious foci and changes in clinical management, defined as changes in the duration or class of antibiotic therapy, a surgical procedure on the source of infection or a change in the decision to remove or retain an implantable device. Results: We included 39 patients (median age: 69 years, IQR: 60–79). Fifteen (39%) patients did not have an infectious focus identified before 18F-FDG-PET/CT. Thirty new infectious foci were detected in 22/39 (56%) patients. In 11/15 (73%) patients without an identified focus at least one infectious focus was detected by 18F-FDG-PET/CT. In 22/26 (85%) patients with implantable devices, 18F-FDG-PET/CT confirmed or ruled out infection or detected local complications. Out of 13 device infections, 10 were detected by 18F-FDG-PET/CT (7/10 for the first time). In 19/39 (49%) patients 18F-FDG-PET/CT results led to changes in clinical management (15 changes in antibiotic therapy, 2 device removals, 2 surgical procedures, 1 avoidance of a surgical procedure). Conclusions: 18F-FDG-PET/CT may be a useful asset in the management of selected SAB cases, allowing the identification of previously undetected infectious foci and optimization of therapy, particularly in patients with endovascular devices. Indication should be made on a case-by-case basis.(AU)

Objetivos: Evaluar el impacto de la 18F-FDG-PET/TC en el diagnóstico y manejo de los pacientes con bacteriemia por Staphylococcus aureus (BSA). Métodos: Análisis post hoc de una cohorte prospectiva de pacientes adultos consecutivos con BSA (enero 2013-diciembre 2017). Se incluyeron aquellos pacientes en los que se realizó una 18F-FDG-PET/TC a criterio del médico tratante. Los criterios de valoración fueron la identificación de nuevos focos infecciosos y los cambios en el manejo clínico (definidos como modificaciones en la duración o clase del tratamiento antibiótico, intervención quirúrgica sobre el foco infeccioso o cambios en la decisión de retirar o mantener un dispositivo implantable). Resultados: Se incluyeron 39 pacientes (edad media: 69 años; RIC: 60-79). En 15 (39%) pacientes no se había identificado un foco infeccioso antes de la 18F-FDG-PET/TC. Se identificaron 30 nuevos focos infecciosos en 22/39 (56%) pacientes. En 11/15 (73%) pacientes sin un foco infeccioso identificado la 18F-FDG-PET/TC detectó al menos un foco infeccioso. En 22/26 (85%) pacientes con dispositivos implantables la 18F-FDG-PET/TC permitió confirmar/descartar infección del dispositivo o detectar complicaciones locales. Diez de 13 infecciones de dispositivos fueron detectadas por 18F-FDG-PET/TC (7/10 desconocidas previamente). En 19/39 (49%) pacientes los hallazgos en la 18F-FDG-PET/TC conllevaron cambios en el manejo clínico (15 modificaciones de tratamiento antibiótico, 2 retiradas de dispositivo, 2 intervenciones quirúrgicas, un procedimiento quirúrgico evitado). Conclusiones: La 18F-FDG-PET/TC puede ser de utilidad en la BSA, ya que permite identificar nuevos focos infecciosos y modificar el manejo clínico, sobre todo en pacientes con dispositivos endovasculares. La indicación ha de individualizarse en cada paciente.(AU)

Relevance of [18F]FDG-PET/CT in the detection of colon pathology, in patients studied by bacteriemia or infectious endocarditis caused by enteropathogenic microorganisms.

PURPOSE: Association between S. gallolyticus infective endocarditis (IE) and malignant lesions of the gastrointestinal tract is well described. We hypothesize that other enteropathogenic microorganisms, such as S. viridans and E. faecalis are also related with colorectal pathology. Our aim is to determine the frequency of focal colorectal FDG deposits, suggestive of tumoral lesions and their correlation with colorectal pathology, in patients with infection caused by different commensal microorganisms of the gastrointestinal tract. METHODS: We retrospectively examined 61 patients diagnosed with bacteremia (BSI) and IE (possible or definite) according to Duke's criteria, caused by enteropathogenic microorganisms, who underwent a full-body [18F]FDG-PET/CT in our institution. We looked for colorrectal FDG deposits and morphological lesions. All IE patients underwent a complete colonoscopy and the histological results were classified into four groups: malignant lesion, premalignant lesion, benign lesion and no lesion. We evaluated the correlation between the findings of the [18F]FDG-PET/CT with the histopathological diagnosis and the involved microorganism. RESULTS: PET/CT detected 20 colorectal FDG deposits (32.79%-OR: 47.28), 2 within bacteriemic patients (16.7%) confirmed as malignant and premalignant lesions and 18 in IE group (36.6%), 17 of them corresponding to colorrectal pathology: 11 malignant, 5 premalignant and 1 benign lesions. In the IE subgroup, the colonoscopy detected colorectal lesions in 51.02% of the patients: 11malignant, 8premalignant and 6benign. We found a higher incidence of colorectal FDG deposits in Streptococcus spp. subgroup. Regarding the anatomopathological colonic findings there was a predominance of patients affected by S. viridans, followed by E. faecalis and S. gallolyticus. CONCLUSION: Patients studied by PET/CT for systemic infection, especially IE, caused by S. viridans or E. faecalis, in addition to S. gallolyticus, show a greater probability of presenting incidental colorectal FDG deposits, mostly corresponding to malignant or pre-malignant lesions. Therefore, it is necessary to carry out an exhaustive search of possible colorectal foci in these exams.

Impact of 18F-FDG-PET/CT on the management of Staphylococcus aureus bacteraemia: a retrospective observational study.

OBJECTIVES: To assess the impact of 18F-FDG-PET/CT on the diagnosis and management of patients with Staphylococcus aureus bacteraemia (SAB). METHODS: Post hoc analysis of a prospective cohort of consecutive adult patients diagnosed with SAB (January 2013-December 2017). Patients who underwent 18F-FDG-PET/CT at the discretion of the attending physician were included. Endpoints were the identification of previously unknown infectious foci and changes in clinical management, defined as changes in the duration or class of antibiotic therapy, a surgical procedure on the source of infection or a change in the decision to remove or retain an implantable device. RESULTS: We included 39 patients (median age: 69 years, IQR:60-79). Fifteen (39%) patients did not have an infectious focus identified before 18F-FDG-PET/CT). Thirty new infectious foci were detected in 22/39 (56%) patients. In 11/15 (73%) patients without an identified focus at least one infectious focus was detected by 18F-FDG-PET/CT. In 22/26 (85%) patients with implantable devices, 18F-FDG-PET/CT confirmed or ruled out infection or detected local complications. Out of 13 device infections, 10 were detected by 18F-FDG-PET/CT (7/10 for the first time). In 19/39 (49%) patients 18F-FDG-PET/CT results led to changes in clinical management (15 changes in antibiotic therapy, 2 device removals, 2 surgical procedures, 1 avoidance of a surgical procedure). CONCLUSIONS: 18F-FDG-PET/CT may be a useful asset in the management of selected SAB cases, allowing the identification of previously undetected infectious foci and optimization of therapy, particularly in patients with endovascular devices. Indication should be made on a case-by-case basis.

Evaluation of survival of the patients with metastatic rectal cancer by staging 18F-FDG PET/CT radiomic and volumetric parameters.

OBJECTIVE: The aim of this study is to predict the prognosis in patients with metastatic rectal cancer (mRC) by obtaining a model with machine learning (ML) algorithms through volumetric and radiomic data obtained from baseline 18-Fluorine Fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) images. METHODS: Sixty-two patients with mRC who underwent 18F-FDG PET/CT imaging for staging between January 2015 and January 2021 were evaluated using LIFEx software. The volume of interest (VOI) of the primary tumor was generated and volumetric and textural features were obtained from this VOI. In addition, metabolic tumor volume (tMTV) and total lesion glycolysis (tTLG) values of tumor foci in the whole body. Clinical and radiomic data were evaluated with ML algorithms to create a model that predicts survival. Significant associations between these features and 1-year and 2-year survival were investigated. RESULTS: Random forest algorithm was the most successful algorithm in predicting 2-year survival (AUC: 0.843, PRC: 0.822, and MCC: 0.583). The model obtained with this algorithm was able to predict 49 patients with 79.03% accuracy. While tMTV and tTLG values were successful in predicting 1-year survival (p: 0.002 and 0.007, respectively), texture characteristics from the primary tumor did not show a significant relationship with 1-year survival. CONCLUSIONS: In addition to the important role of 18F-FDG PET/CT in staging patients with mRC, this study shows that it is possible to predict survival with ML methods, with parameters obtained using texture analysis from the primary tumor and whole body volumetric parameters.

Contribución de las imágenes PET/TC con 18F-FDG en el diagnóstico y manejo de pacientes VIH positivos / Contribution of 18F-FDG PET/CT imaging in the diagnosis and management of HIV-positive patients

Objetivo El virus de la inmunodeficiencia humana (VIH) es un lentevirus, que infecta principalmente ciertas células del sistema inmunitario, por lo que debilita las defensas propias frente a las enfermedades. El objetivo de este estudio fue valorar la significación de la PET/TC con 18F-FDG en la evaluación de pacientes con infección por VIH y determinar la presencia de diferencias cuantitativas de captación de 18F-FDG entre pacientes con infecciones relacionadas con el VIH o neoplasia maligna en pacientes VIH positivos. Métodos Se estudiaron 40 pacientes con infección por VIH mediante PET/TC con 18F-FDG. Se registró el estado inmunitario, el tratamiento antirretroviral y el diagnóstico definitivo de cada paciente. Se describieron todas las lesiones patológicas y áreas relacionadas con la enfermedad, se evaluaron los patrones de captación de 18F-FDG. Se realizó un análisis semicuantitativo de la captación de 18F-FDG mediante el cálculo SUVmax. Resultado Veintiocho pacientes (70%) fueron diagnosticados con infección relacionada con el VIH o neoplasia maligna. La sensibilidad de la PET/TC con 18F-FDG fue del 100% y la especificidad del 92% para las enfermedades concomitantes que requerían tratamiento adicional a la terapia antirretroviral. El SUVmax y el recuento de CD4 no fueron estadísticamente diferentes entre la linfadenopatía reactiva relacionada con el VIH, la neoplasia maligna relacionada con el VIH y las infecciones relacionadas con el VIH. Conclusiones El patrón de distribución de la captación ganglionar/extraganglionar en la PET/TC con 18F-FDG puede facilitar la distinción entre las adenopatías generalizadas relacionadas con el VIH, las infecciones oportunistas relacionadas con el VIH y las neoplasias malignas. En este contexto, se debe realizar el estudio PET/TC con 18F-FDG de forma rutinaria en el manejo de pacientes infectados por el VIH (AU)

Introduction and objectives The human immunodeficiency virus [HIV] is a lentevirus, primarily infects certain cells of the immune system, thereby greatly weakens the body's own defenses against diseases. This study was aimed to explore the value and significance of 18F-FDG PET/CT in the assessment of patients with HIV infection and to examine the presence of quantitative alterations in 18F-FDG uptake among patients with HIV-related infections or malignant diseases in HIV-positive patients. Patients and methods Forty patients with HIV infection were scanned on PET/CT system. The data were registered according to immune status, antiretroviral therapy, and definitive diagnosis. All pathologic lesions and disease related areas were described, 18F-FDG uptake patterns were evaluated. Semiquantitative analysis of 18F-FDG uptake was performed and SUVmax were calculated. Results Twenty-eight patients [70%] were diagnosed with HIV-related infection or malignant diseases. The sensitivity of PET/CT was shown to be 100% and the specificity 92% for concomitant diseases requiring additional treatment to antiretroviral therapy. The SUVmax and CD4 counts were not statistically different between HIV-related reactive lymphadenopathy, HIV-related malignancy, and HIV-related infections. Conclusions The pattern of distribution of nodal/extranodal uptake on 18F-FDG PET/CT may facilitate distinction between HIV-related generalized lymphadenopathies, HIV-related opportunistic infections, and malignancies. In this context, 18F-FDG PET/CT should be preferred for routine use in the management of patients infected with HIV (AU)

Aplicación clínica de la [18F]FDG PET/TC en el linfoma folicular / Clinical application of [18F]FDG PET/CT in follicular lymphoma

El objetivo de este trabajo fue revisar el papel de la [18F]FDG PET/TC en el linfoma folicular (LF). Tras confirmarse que a pesar de su carácter indolente este tipo de linfoma habitualmente muestra avidez por el radiotrazador, la [18F]FDG PET/TC fue cobrando una importancia progresivamente mayor hasta ser considerada como la técnica de elección para su estadificación, re-estadificación y valoración de respuesta al tratamiento. Múltiples estudios han demostrado el impacto que supone en el manejo de estos pacientes (puede cambiar el estadio de la enfermedad en una proporción significativa de casos y condicionar modificaciones en el tratamiento), su superioridad respecto a la TC (principalmente por la capacidad para distinguir tejido tumoral viable de tejido fibrótico residual) y su valor pronóstico. Esto último se atribuyó inicialmente de forma exclusiva al grado de respuesta metabólica alcanzado tras el tratamiento, que ha probado ser un factor predictivo fuerte e independiente de supervivencia libre de progresión (SLP) y supervivencia global (SG), de modo que una [18F]FDG PET/TC negativa podría considerarse una garantía para los pacientes con LF con elevada carga tumoral. No obstante, la obtención de parámetros metabólicos semicuantitativos como el volumen metabólico tumoral o la glucólisis total de la lesión podría también aportar información a este respecto y ayudarnos potencialmente a identificar a los pacientes de mal pronóstico antes del inicio del tratamiento, de forma que se pueda adecuar el manejo y seguimiento al riesgo del paciente (AU)

The objective of the present paper was to review the clinical application of [18F]FDG PET/CT in follicular lymphoma (FL). Once it was clear that, despite it's characterized as indolent, this type of lymphoma usually shows a high [18F]FDG avidity, PET/CT became more important and it's now considered the standard technique in staging, re-staging and response evaluation. Many studies have shown its impact on the management of patients (as it can change the stage in a significant proportion of cases and lead to treatment modifications), its superiority over CT (mainly because it's able to distinguish fibrosis in residual masses from viable tumor) and its prognostic value. The latter was initially associated only to the degree of metabolic response, which has proved to be a strong and independent predictive factor in terms of disease-free survival (DFS) and overall survival (OS). Thus, a negative PET/CT scan could be considered a guarantee in high-tumor-burden follicular lymphoma patients. However, semiquantitative parameters such as metabolic tumor volume or total lesion glycolysis, may also provide useful information and help us to identify patients with poor prognosis, guiding a risk-adjusted management and follow-up (AU)

Clinical application of [18F]FDG PET/CT in follicular lymphoma.

The objective of the present paper was to review the clinical application of [18F]FDG PET/CT in follicular lymphoma (FL). Once it was clear that, despite it is characterized as indolent, this type of lymphoma usually shows a high [18F]FDG avidity, PET/CT became more important and it's now considered the standard technique in staging, re-staging and response evaluation. Many studies have shown its impact on the management of patients (as it can change the stage in a significant proportion of cases and lead to treatment modifications), its superiority over CT (mainly because it's able to distinguish fibrosis in residual masses from viable tumor) and its prognostic value. The latter was initially associated only to the degree of metabolic response, which has proved to be a strong and independent predictive factor in terms of disease-free survival (DFS) and overall survival (OS). Thus, a negative PET/CT scan could be considered a guarantee in high-tumor-burden follicular lymphoma patients. However, semiquantitative parameters such as metabolic tumor volume or total lesion glycolysis, may also provide useful information and help us to identify patients with poor prognosis, guiding a risk-adjusted management and follow-up.

Methodological Aspects and the Prognostic Value of Metabolic Tumor Volume assessed with 18F-FDG PET/CT in Lymphomas.

Although metabolic tumor volume (MTV) assessed with pretreatment 18F-FDG PET/CT has shown significant prognostic value across many lymphoma types, it is still not used in clinical practice due to technical concerns and the lack of standardisation. Numerous studies on the prognostic value of MTV in lymphomas have been published in recent years, but there is still no full agreement on the best methodology for MTV calculation. In this paper, we reviewed the methodological aspects of MTV assessment and reported recent works about its impact on outcome in lymphomas, with a focus on Hodgkin lymphoma (HL) and diffuse large B cell lymphoma (DLBCL).

Contribution of 18F-FDG PET/CT imaging in the diagnosis and management of HIV-positive patients.

INTRODUCTION AND OBJECTIVES: The human immunodeficiency virus [HIV] is a lentevirus, primarily infects certain cells of the immune system, thereby greatly weakens the body's own defenses against diseases. This study was aimed to explore the value and significance of 18F-FDG PET/CT in the assessment of patients with HIV infection and to examine the presence of quantitative alterations in 18F-FDG uptake among patients with HIV-related infections or malignant diseases in HIV-positive patients. PATIENTS AND METHODS: Forty patients with HIV infection were scanned on PET/CT system. The data were registered according to immune status, antiretroviral therapy, and definitive diagnosis. All pathologic lesions and disease related areas were described, 18F-FDG uptake patterns were evaluated. Semiquantitative analysis of 18F-FDG uptake was performed and SUVmax were calculated. RESULTS: Twenty-eight patients [70%] were diagnosed with HIV-related infection or malignant diseases. The sensitivity of PET/CT was shown to be 100% and the specificity 92% for concomitant diseases requiring additional treatment to antiretroviral therapy. The SUVmax and CD4 counts were not statistically different between HIV-related reactive lymphadenopathy, HIV-related malignancy, and HIV-related infections. CONCLUSIONS: The pattern of distribution of nodal/extranodal uptake on 18F-FDG PET/CT may facilitate distinction between HIV-related generalized lymphadenopathies, HIV-related opportunistic infections, and malignancies. In this context, 18F-FDG PET/CT should be preferred for routine use in the management of patients infected with HIV.

18F-FDG-PET/CT in SARS-CoV-2 infection and its sequelae.

In recent months, much of the scientific efforts have focused on research on SARSCoV-2 infection and its consequences in humans. Still, many aspects remain unknown. It is known that the damage caused by SARS-CoV-2 is multifactorial and that its extension goes beyond lung inflammation and the acute phase, with the appearance of numerous complications and sequelae. To date, knowledge about the usefulness of 18F-FDG-PET/CT in the acute phase has been limited to the incidental detection of SARS-CoV-2 unsuspected pneumonia. Recent studies have been appearing collecting the findings of 18F-FDG-PET/CT in long COVID-19 or persistent COVID-19 state as well as the alterations caused after mass vaccination of the population in the metabolic studies. This work aims to review the existing literature focusing on these three issues and to briefly present our own preliminary experience.

IgG4 related disease. / Enfermedad relacionada con IgG4.

IgG4-related disease (ER-IgG4) is a recognised systemic disease. It was described after patients diagnosed with autoimmune pancreatitis showed signs of extra-pancreatic disease. The clinical manifestation of these patients is subacute and is manifested by the appearance of pseudotumoral lesions, or inflammatory or fibrous tumours. Sometimes it can be serious as in the case of patients with cholangitis or large vessel vasculitis. Diagnostic criteria include, among others, serum IgG4 elevation and/or histological parameters. The 18F-FDG-PET/CT is useful in the initial diagnosis, biopsy guidance as well as in the assessment of response to therapy. It usually responds to steroid therapy.

The role of 18F-FDG PET/CT in the management of Merkel cell carcinoma: The experience of 51 studies in our institution. / Papel de la 18F-FDG PET/TC en el manejo del carcinoma de células de Merkel: experiencia de 51 estudios en nuestra institución.

OBJECTIVES: Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine tumor with limited evidence on the role of 18F-FDG PET/CT. The aim of this study was to assess the impact of the 18F-FDG PET/CT in the management of MCC. METHODS: Fifty-one studies of 18F-FDG PET/CT of 35 patients (19 men [54.30%]; 72.17±14.63years) with histologic diagnosis of MCC were retrospectively evaluated. The change in tumor staging and the impact on the treatment were analysed. RESULTS: There were 23 PET/CT positive studies (45.10%) and 28 (54.90%) negative. Thirty four (66.7%) studies were performed for assessment of stage at initial presentation and 17 (33.3%) were performed during the follow up: 6 (35.29%) for suspected recurrence; 7 (41.18%) for restaging; 4 (23.53%) as a part of ongoing surveillance. On the basis of PET/CT results, there was a change in disease stage (SC) in 20 studies (39.20%) and impact in the management (MI) in 28 (54.90%): 11 (32.40%) SC and 12 (35.30%) MI in the initial staging; 5 (71.43%) SC and 7 (100%) MI in the restaging; 3 (50.00%) SC and 6 (100%) MI in suspected recurrence; 1 (25.00%) SC and 3 (75.00%) MI in the surveillance. 18F-FDG PET/CT incidentally detected one additional histologically confirmed cancer. The presence of nodal involvement in the beginning (0.0098; HR 3.82; 95%CI: 1.38-10.6), chemotherapy treatment (6e-04; HR 7.06; 95%CI: 2.30-21.60), size of primary tumor >2cm (6e-04; HR 7.06; 95%CI: 2.30-21.60) and positive resection margin (0.00069; HR 4.01; 95%CI: 1.46-11.00) were statistically significant prognostic factors for overall survival. There was a trend towards significance for worse overall survival with initial positive 18F-FDG PET/CT but the trend did not reach statistical significance. CONCLUSION: 18F-FDG PET/CT altered the stage in 2 out of 5 studies and changed the treatment in more than half of the studies performed. The study confirms the important impact of 18F-FDG PET/CT on the management of MCC patients.