Evaluation of the prognostic value of the metabolic volumetric parameters calculated with 18F-FDG PET/CT and its value added to the molecular characteristics in patients with diffuse large B-cell lymphoma.

INTRODUCTION AND OBJECTIVES: Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are prognostic predictors in patients with diffuse large B-cell lymphoma (DLBCL). The objective of this study is to evaluate the prognostic impact of the baseline volumetric parameters calculated with positron emission tomography/computed tomography with 18F-fluorodeoxyglucose (18F-FDG PET/CT) and its added value to the molecular characteristics in patients with DLBCL not otherwise specified (NOS). METHODOLOGY: This is a retrospective observational study, which included 35 patients who underwent a baseline 18F-FDG PET/CT prior to treatment. A univariate analysis of the volumetric parameters (MTV and TLG), immunohistochemical study and chromosomal translocations were performed. The method for calculating the volumetric parameters was the SUV 2.5 threshold. The comparison between the predictive models was selected based on the information criterion value of Akaike (AIC), bayesian (BIC) and Harrell's C, after performing a Cox proportional hazards regression model. In addition, a univariate analysis of the volumetric parameters was performed according to the data of the immunohistochemical study using the Wilcoxon-Mann-Whitney test. RESULTS: A univariate analysis revealed that VMT and TLG are predictors of progression-free survival (PFS) and overall survival (OS), with a high discrimination capacity. Adding VMT and TLG to the immunohistochemical study and chromosomal translocation provided a better prognostic value for PFS and OS in patients diagnosed with DLBCL-NOS. Likewise, it was evidenced that the values of the volumetric parameters were lower in patients who presented a germinal center B cell phenotype (GCB) compared to patients with an activated B cell phenotype (ABC) who presented higher values. CONCLUSION: MTV and TLG added to the immunohistochemical study and chromosomal translocation provided a better prognostic value for PFS and OS in patients diagnosed with DLBCL-NOS.

Evaluation of the prognostic value of different methods of calculating the tumour metabolic volume with 18F-FDG PET/CT, in patients with diffuse large cell B-cell lymphoma. / Evaluación del valor pronóstico de los diferentes métodos de cálculo del volumen metabólico tumoral con 18F-FDG PET/TC, en pacientes con linfoma B difuso de células grandes.

INTRODUCTION AND OBJECTIVES: Metabolic tumor volume (MTV) is a promising indicator of prognosis in diffuse large B-cell lymphoma (DLBCL). The aim of the present study is to evaluate the different methods for the calculation of the basal metabolic tumor volume with 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in the patients with DLBCL, relating each one of the volumes measured with progression-free survival (PFS) and overall survival (OS). METHODOLOGY: This is a retrospective analytical cohort study, in which 34 patients underwent to 18F-FDG PET/CT baseline prior to treatment. We compared three SUV thresholds 2.5, SUV 40% of the maximum SUV and SUV mean hepatic uptake (PERCIST) for the calculation of MTV and total lesion glycolysis (TLG) biomarkers, relating them to the PFS and OS. The best predictive model was selected based on the Akaike's information criterion (AIC) after performing a Cox proportional hazards regression. RESULTS: In relation to the PFS, they show statistically significant differences: MTV 2.5, TLG 2.5, MTV 40, TLG 40, MTV and TLG calculated with the PERCIST threshold. Among these, the one that has a lower AIC is MTV 2.5, so it is considered the best parameter to predict the PFS. With respect to OS, it shows statistically significant differences: MTV 2.5, VMT and TLG calculated with the PERCIST threshold. Among these three, the one with the lowest AIC is MTV 2.5, which is why it is considered the best parameter to predict OS. In addition, a higher value of MTV and total tumor glycolysis (TLG), is associated with worse PFS and OS CONCLUSION: The MTV calculated with the threshold SUV 2.5 seems to be the best parameter to predict PFS and OS in patients diagnosed with DLBCL with 18F-FDG PET/CT.

[Diagnosis of COVID-19 pneumonia in asymptomatic patients after an oncological PET/CT]. / Diagnóstico de neumonía COVID-19 en pacientes asintomáticos tras la realización de un PET/TC oncológico.

INTRODUCTION: On January 30, 2020, the World Health Organization (WHO) declared an international emergency due to the pandemic caused by a new coronavirus. There are some oncological indications that have special priority and studies are still being carried out despite the current situation. In these studies we have found suspicious findings of COVID-19 pneumonia in asymptomatic patients. The objective of this work is to assess the incidence of these findings, describe their characteristics and the evolution of suspected patients. MATERIAL AND METHODS: Oncological PET studies carried out in asymptomatic patients between March 18 and April 8, 2020 have been reviewed. Patients who presented findings suggestive of corresponding to an pulmonary infectious process were selected. Clinical findings have been reviewed to confirm or rule out SARS-CoV-2 infection. RESULTS: During the specified period, a total of 129 PET/CT studies were performed. Of these, 11 (8.5%) found suspicious findings of a pulmonary infectious process. These were 8 men and 3 women aged between 30 and 79 years (mean 62.2). CONCLUSIONS: Patients with COVID-19 can present few symptoms of the disease, and in PET/CT studies both presymptomatic and almost asymptomatic patients can be detected, so nuclear medicine physicians should take special attention to the pulmonary evaluation of PET/CT studies.

Criteria of metabolic response to immunotherapy. / Criterios de respuesta metabólica a la inmunoterapia.

Therapy response assessment is one of the most challenging indications of imaging studies. In clinical trial patients is usually measured with standardized response criteria. However, in the clinical practice, many studies are carried out in which the clinical question is whether or not the treatment is being effective. Answering this question is one of the greatest challenges for diagnostic imaging physicians, especially when a new treatment modality is being introduced, whose effects on tumoral lesions are firstly poorly understood. We have an essential role in the introduction of new therapies, assessing their effects and benefits. The knowledge of these effects has led to the development of many response criteria that, despite being applicable only in clinical trials, offer us information on how to interpret the findings in clinical practice.

Prognostic significance of metabolic tumor volume and total lesion glycolysis in patients with advanced cervical carcinoma. / Significación pronóstica del volumen metabólico tumoral y de la glucólisis tumoral total en pacientes con cáncer cervical avanzado.

AIM: 18-Fluoro-2-deoxy-d-glucose positron emission tomography (18F-FDG PET/CT) is considered to be the most accurate image method of detection of node or distant metastases in cervical cancer. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of 18F-FDG PET/CT are volumetric measurements of tumor cells with increased 18F-FDG uptake. The prognostic value of MTV and TLG in patients with advanced cervical cancer (ACC) were evaluated. METHODS: 38 patients with ACC from one tertiary university hospital underwent 18F-FDG PET/CT between June 2009 and December 2015. Clinicopathologic factors and various PET parameters were analyzed to evaluate their relationship with recurrence-free survival (RFS) and overall survival (OS). These parameters were: maximum standardized uptake value (SUVmax), mean standardized uptake value (SUV mean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor, of the pelvic nodes, of the paraaortic nodes and the metabolic volume of the metastases if any. RESULTS: A total of 38 patients with ACC fulfilled the inclusion criteria. All of them underwent a 18F-FDG PET/CT before definitive chemoradiotherapy. In the univariate analyses higher tumor size, pelvic lymph node metastasis and both MTV and TLG showed a significant association with OS and with RFS (MTV HR=1.55, p=0.011 and TLG HR=1.43, p=0.017 for RFS and MTV HR=1.82, p=0.006 and TLG HR=1.67, p=0.007 for OS). CONCLUSION: Pretreatment TLG sum and MTV sum seem to be independent prognostic factors for OS and RFS in patients with advanced cervical cancer treated with definitive chemoradiotherapy and they are better than the classic measurement of SUVmax.

Can positron emission tomography support the characterization of immune-mediated inner ear disease? / ¿Puede la tomografía por emisión de positrones ayudar en la caracterización de la enfermedad inmunomediada del oído interno?

INTRODUCTION: To evaluate the utility of 18F-FDG PET/TC as an imaging tool for the characterization of immune-mediated inner ear disease (IMIED), providing measurements of the inner ear region activity as well as detecting possible involvement of other organs. MATERIAL AND METHODS: The study included 28 patients with IMIED and 4 sex-matched and age-matched control subjects with no history of ear disease. Eighteen patients were considered to be suffering from primary IMIED and 10 patients from secondary. PET/CT scans with 18F-FDG were performed to assess systemic involvement as well as inner ear region activity. Interpretation of PET/CT scans was performed independently by 2nuclear medicine physicians blinded to clinical history. In order to assess inter-rater agreement before performing the analysis of the inner ear, different Bland & Altman plots and the intraclass correlation coefficients were estimated. RESULTS: Different metabolically active foci findings were reported in 13 patients. Four patients diagnosed as primary IMIED showed thyroid and aorta activity. Regarding the inner-ear semiquantitative analysis, the inter-rater agreement was not sufficiently high. Comparisons between groups, performed using Mann-Whitney test or Kruskal-Wallis tests, showed no differences. CONCLUSIONS: The study showed 18F-FDG PET/TC could be an important tool in the evaluation of IMIED as it can support the characterization of this entity providing the diagnosis of unknown or underestimated secondary IMIED. Nevertheless, we consider PET is not an adequate tool to approach the inner ear because of the small size and volume of the cochlea which makes the assessment very difficult.

18F-Choline PET/CT scan in staging and biochemical recurrence in prostate cancer patients: Changes in classification and radiotherapy planning. / La PET/TC con 18F-Colina en la estadificación y recidiva bioquímica de pacientes con cáncer de próstata: cambios en la clasificación y planificación de radioterapia.

OBJECTIVE: To evaluate the role of the 18F-Choline PET/CT in prostate cancer management when detecting distant disease in planning radiotherapy and staging and to evaluate the therapy changes guided by PET/TC results. MATERIAL AND METHODS: A retrospective evaluation was performed on 18F-Choline PET/CT scans of patients with prostate cancer. Staging and planning radiotherapy scans were selected in patients with at least 9 months follow up. There was a total of 56 studies, 33 (58.93%) for staging, and 23 (41.07%) for planning radiotherapy. All scans were obtained using a hybrid PET/CT scanner. The PET/CT acquisition protocol consisted of a dual-phase procedure after the administration of an intravenous injection of 296-370MBq of 18F-Choline. RESULTS: There were 43 out of 56 (76.8%) scans considered as positive, and 13 (23.2%) were negative. The TNM staging was changed in 13 (23.2%) scans. The PET/CT findings ruled out distant disease in 4 out of 13 scans, and unknown distant disease was detected in 9 (69.3%) scans. CONCLUSIONS: 18F-Choline PET/CT is a useful technique for detecting unknown distant disease in prostate cancer when staging and planning radiotherapy. The inclusion of 18F-choline PET/CT should be considered in prostate cancer management protocols.

Clinical-scintigraphy discordance in a case of malignant external otitis.

We report the case of an immunocompromised female patient with external otitis, who developed a picture of external otitis with poor response to conventional treatment and subsequent isolation of Pseudomona Aeruginosa in the ear secretion culture. The final diagnosis was malignant external otitis. Our objective is to describe the scintigraphic findings as well as to analyze their correlation with the clinical pattern and to evaluate the possible causes of the discordance found.

Contribution of the portable gamma camera to detect the sentinel node in breast cancer during surgery.

AIM: To show our experience using the portable gamma camera during surgery in the detection of the sentinel node in breast cancer. MATERIAL AND METHODS: A total of 46 women diagnosed with breast cancer were included. This study was carried out by means of the periareolar intradermal injection. Planar images and SPECT/CT were acquired. On the following day, the sentinel nodes were localized intraoperatively with a portable gamma camera and a gamma probe. Images of the anterior axillary line projection and lateral axillary line projection were acquired before and after extraction of all the sentinel nodes. RESULTS: The images acquired with the portable gamma-camera during the operation showed no activity in all of the patients after the removal of the sentinel nodes. In four out of the 46 cases, the portable gamma camera provided relevant information during the procedure (it detected a sentinel node in two cases in which it had not been detected prior to the surgery and it oriented the surgeon in the localization of low activity nodes when the probe screening had been negative). CONCLUSIONS: The use of the intraoperative portable gamma camera to detect the sentinel node in breast cancer patients is useful in order to ensure, independently of the surgeon, that all the sentinel nodes have been removed. It can also help guide the surgeon in the event of a single low activity sentinel node.

[The impact on diagnostic quality of using contrast media in PET-CT studies]. / Calidad diagnóstica y repercusión del empleo de contrastes en los estudios de tomografía computarizada de exploraciones con tomografía por emisión de positrones en combinación con tomografía computarizada.

OBJECTIVE: To evaluate the impact of using radiologic contrast media on the quality of PET-CT studies at our center. MATERIAL AND METHODS: This is a retrospective observational study to evaluate the quality of the PET-CT studies carried out with radiologic contrast media and the presence of artifacts due to these contrast agents. Oncologic patients in whom PET was indicated according to the manufacturer's specifications for FDG ((18)F-2-fluoro-2-deoxy-D-glucose) underwent PET-CT study on a PET-CT system with a six-detector-row CT scanner. RESULTS: Between February 2009 and June 2009, we performed 612 PET-CT examinations in 369 male patients and 243 female patients. Iodinated contrast media were administered intravenously in 48% and orally in 18%. Diagnostic quality was considered high in 93.5% of the studies, intermediate in 4.3%, and low in 2.2%. In the CT studies performed using intravenous contrast agents, artifacts were identified in 8% and resulted in diagnostic uncertainty in the PET study in 1.4%. We found no diagnostic problems caused by oral contrast agents in any case. CONCLUSIONS: The use of radiologic contrast agents in PET-CT studies does not negatively affect diagnostic quality or workflow. Given that we can improve the ability of PET-CT to detect lesions by enhancing the diagnostic quality of the CT study, we consider it appropriate to include the administration of contrast agents in protocols for PET-CT studies.

[SPECT-CT in sentinel node detection in patients with melanoma]. / SPECT-TAC en la localización del ganglio centinela en pacientes con melanoma.

INTRODUCTION: The prognosis of patients with cutaneous melanoma is greatly influenced by the presence of lymph node metastases. One of the most innovative and fascinating concepts to emerge in the field of oncology in recent years is the use of sentinel lymph node biopsy (SLNB). AIM: The aim of this study was to determine what SPECT-CT images contribute to the search for sentinel nodes in patients with melanoma. METHODS: From March 2007 to October 2008, 18 patients were examined for sentinel nodes using dynamic scintigraphy, planar images, and SPECT-CT in the Nuclear Medicine Department of San Carlos University Hospital. The group contained 10 women and 8 men, age range 14-83 years, mean age 57 years (57+/-20.1). RESULTS: The sentinel node was located by conventional imaging techniques (dynamic scintigraphy and planar images) in 16 of 18 patients (88.88%). SPECT-CT identified the sentinel node in 18 of 18 patients (100%) and detected clinically relevant findings in 6 of 18 patients (33.33%) CONCLUSIONS: SPECT-CT imaging contributed clinically relevant information on sentinel nodes of melanoma, which is particularly important in patients with melanoma of the trunk or head and neck.

[SPECT-CT: a new tool for localisation of sentinel lymph nodes in breast cancer patients]. / SPECT-TAC: una nueva herramienta para la localización del ganglio centinela en pacientes con cáncer de mama.

INTRODUCTION: Sentinel lymph node biopsy has become a widely accepted procedure for axillary lymph node staging in patients with breast cancer. AIM: The aim of this study was to determine the advantages of using SPECT-CT instead of planar scintigraphy in the presurgical localisation of sentinel lymph nodes. METHODS: We prospectively included 25 consecutive patients with breast cancer who were admitted to our department for SLN localisation. Patients were divided into two groups, depending on whether neoadjuvant chemotherapy had been received (B, n = 6) or not (A, n = 19). Four doses (1.0 mCi each) of 99mTc-nanocolloid were injected intradermallly in all patients, and SPECT-CT and planar images were acquired. All patients underwent surgery and SLN localisation with a hand-held gamma probe. Any axillary "hot spots" were resected. The kappa index (ki) was calculated using surgical findings as the gold standard. RESULTS: In group A, the SLN was correctly detected in 17/19 patients (89.5 %) with SPECT-CT and in 12/19 (63.2 %) with planar images. The correlation between SPECT-CT and surgical findings (ki 0.91) was better than between planar images and surgical findings (ki 0.57). In group B, the results of SPECT-CT and planar images were identical, with accurate localisation of the SLN in 5/6 patients (ki 0.76). CONCLUSIONS: The results of this study suggest that SPECT-CT may be useful for locating the SLN in breast cancer patients, as it provides accurate localization of the SLN with useful anatomical information. This may allow the surgeon to search exclusively for SLN viewed on SPECT-CT, and avoid false negative and false positive results.