Apport de la TEP/TDM au 18FDG dans la stadification initiale et l’évaluation précoce de la réponse thérapeutique des rhabdomyosarcomes pédiatriques

PurposeThe objective of this study was to retrospectively evaluate the impact of positron emission tomography/computed tomography (PET/CT) using fluorine-18-fluorodeoxyglucose (FDG), in comparison with conventional imaging modalities (CIM), for initial staging and early therapy assessment in paediatric rhabdomyosarcoma.Patients and methodsPrior to treatment, 18 patients (age range, 9 months to 18 years) with histologically proven rhabdomyosarcoma underwent FDG PET/CT in addition to CIM (magnetic resonance imaging of primary site, whole body CT and bone scintigraphy). After three courses of chemotherapy, 12 patients underwent FDG PET/CT in addition to CIM. RECIST criteria and visual analysis of FDG uptake were used for assessment of response. The standard of reference was determined by an interdisciplinary tumor board based on imaging material, histopathology and follow-up data (median = 5 years).ResultsPET/CT sensitivity was superior to CIM's concerning lymph node involvement (100% versus 83%, respectively) and metastases detection (100% versus 50%, respectively). PET/CT results changed therapeutic management in 11% of cases. After three courses of chemotherapy, the rate of complete response was 66% with PET/CT versus 8% with CIM. Five percent of patients relapsed during follow-up (median = 5 years).ConclusionThis study confirms that PET/CT depicts important additional information in initial staging of paediatric rhabdomyosarcomas and suggests a superior prognostic value of PET/CT in early response to chemotherapy assessment.     

Metformin May Be Associated with False-Negative Cancer Detection in the Gastrointestinal Tract on Pet/Ct

ObjectiveConcurrent therapy with the antihyperglycemic drug metformin can hinder the detection of malignancy in the abdominal and pelvic portions of ¹⁸F-fluordeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging performed for the diagnosis or staging of malignancy, as well as for treatment response and radiation therapy planning. This is due to the metformin-induced increase in intestinal FDG radiotracer uptake. We aim to bring this potentially important interaction to the attention of clinicians who care for cancer patients with diabetes.MethodsWe searched MEDLINE (from 1970 to January 2014)and Google Scholar for relevant English-language articles using the following search terms: “metformin and FDG/PET, metformin and bowel uptake, metformin, and cancer, metformin and the intestine, metformin pharmacokinetics, hyperglycemia and FDG/PET.” We reviewed the reference lists of pertinent articles with respect to metformin gut physiology, impact on FDG uptake and the effect on diagnostic accuracy of abdominal-pelvic PET/CT scans with concurrent metformin therapy.ResultsWe reviewed the action of metformin in the intestine, with particular emphasis on the role of metformin in PET/CT imaging and include a discussion of clinical studies on the topic to help refine knowledge and inform practice. Finally, we discuss aspects pertinent to the management of type 2 diabetes (T2D) patients on metformin undergoing PET/CT.ConclusionsMetformin leads to intense, diffusely increased FDG uptake in the colon, and to a lesser degree, the small intestine, which limits the diagnostic capabilities of FDG PET/CT scanning and may mask gastrointestinal malignancies. We suggest that metformin be discontinued 48 hours before FDG PET/CT scanning is performed in oncology patients. More rigorous data are needed to support the widespread generalizability of this recommendation. (Endocr Pract. 2014;20:1079-1083)     

Intérêt de la tomographie par émission de positons (TEP) au 18FDG dans le suivi des patients traités pour carcinome épidermoïde des voies aérodigestives supérieures (VADS) en rémission clinique

IntroductionPosttreatment follow-up of head and neck squamous cell carcinoma (HNSCC) recurrence is a diagnostic challenge. Tissue distortions from radiation and surgery can obscure early detection of recurrence by conventional follow-up approaches such as physical examination (PE), computed tomography, and magnetic resonance imaging. A number of studies have shown that ¹⁸Fluoro-fluorodeoxyglucose (¹⁸FDG) Positron emission tomography (PET) may be an effective technique for the detection of persistent, recurrent, and distant metastatic HNSCC after treatment. The aim of this prospective study was to determine the benefits (sensitivity, specificity, predictive values, and accuracy) of ¹⁸FDG PET using hybrid PET–Computed tomography system (PET/CT) in the detection of HNSCC subclinical locoregional recurrence and distant metastases, in patients 12 months after curative treatment with a negative conventional follow up.Materials and MethodsNinety-one patients cured from head and neck squamous cell carcinoma (HNSCC) without any clinical element for recurrence were included. Whole-body ¹⁸FDG PET/CT examination was performed 11.6 ± 4.4 months after the end of the treatment. The gold standard was histopathology or 6 months imaging follow-up.ResultsThe whole-body ¹⁸FDG PET/CT of the 91 patients in this study consisted of 52 negative and 39 positive results. Nine of these patients who exhibited abnormal ¹⁸FDG uptake in head and neck area did not have subsequently proven recurrent HNSCC (false positive). Thirty had proven recurrence (true positive). All 52 patients with negative readings of ¹⁸FDG PET/CT remained free of disease at 6 months (true negative). The sensitivity and specificity of ¹⁸FDG PET/CT in this study for the diagnosis of HNSCC recurrence were 100% (30/30) and 85% (52/61) respectively. The positive predictive value was 77% (30/39). The negative predictive value was 100% (52/52). The overall accuracy was 90% (82/91).ConclusionThe results of our study confirm the high effectiveness of ¹⁸FDG PET/CT in assessment of HNSCC recurrence. It suggests that this modality is more accurate than conventional follow-up PE alone in the assessment of patient recurrence after previous curative treatment for HNSCC. Therefore, a PET study could be systematically proposed at 12 months after the end of the treatment.     

La fixation vasculaire du 18FDG est reliée au risque d’événements récents ou futurs chez les patients à haut risque cardiovasculaire

With this study, we sought to identify plaque inflammation as assessed by ¹⁸FDG uptake on positron emission tomography (PET)/computed tomography (CT) as an independent cardiovascular risk factor in patients at high risk for cardiovascular events. We compared 31 consecutive cancer patients presenting with visually enhanced ¹⁸FDG uptake in arterial walls on PET/CT (Group 1) to a selection of 34 matched cancer patients not showing arterial uptake (Group 2). All patients were followed for two years before and six months after PET/CT… Cardiovascular events were classified as older (>6 months before PET/CT) or recent (<6 months before or after PET/CT). ¹⁸FDG uptake was computed on non-attenuation corrected data by a AW/L ratio: mean Arterial Wall uptake/Lung uptake in a normal area, and by SUV on corrected data. A calcium score (CS) was also calculated. ¹⁸FDG uptake and CS were higher in Group 1 than Group 2 (both p = 0.02), and older and recent cardiovascular events were significantly more frequent in Group 1 than Group 2 (p = 0.001 and p = 0.03, respectively). Among the following parameters: number of conventional risk factor, calcium score and presence of ¹⁸FDG uptake, only the latter was significantly related to the occurrence of a recent event by multivariate analysis (p = 0.02). Patients with elevated arterial ¹⁸FDG uptake have a high risk of immediate or future cardiovascular events. Arterial ¹⁸FDG uptake is an indicator of evolving atherosclerotic process and can indicate future cardiovascular events.     

Comparison of 68GA-FAPI-04 PET/CT and 18F-FDG PET/CT in detection of metastatic bone disease in various cancers

ObjectiveOur aim in this retrospective study was to compare the diagnostic accuracy of ⁶⁸Ga-FAPI-04 PET/CT and ¹⁸F-FDG PET/CT in detecting bone metastases of various cancers and to evaluate the potential usefulness of ⁶⁸Ga-FAPI-04 PET/CT in detecting metastatic bone disease.Material and methodOur retrospective study included 44 patients diagnosed with bone metastases due to various cancers between January 2021 and February 2022. All patients underwent ⁶⁸Ga-FAPI-04 PET/CT and ¹⁸F-FDG PET/CT imaging within 14 days. In the semi-quantitative analysis of the skeletal system, all regions with higher uptake than background activity were considered pathological. SUVmax and Metastasis-to-background ratio (TBR) values were calculated from metastatic sites.ResultsA total of 827 bone metastases were detected in our study. The diagnostic accuracies of FAPI PET/CT and ¹⁸F-FDG PET/CT were 91.8% and 81.5%, respectively (P < 0.001). When all bone metastases were compared, the SUVmax of ⁶⁸Ga-FAPI-04 PET/CT was statistically significantly higher than that of ¹⁸F-FDG PET/CT (median 6.15 vs. 5.2; P < 0.001). When FDG and FAPI SUVmax values were compared according to metastasis types, FAPI SUVmax and TBR values in osteolytic, medullary and mixed type bone metastases were found to be statistically significantly higher than FDG (P-values: < 0.001, < 0.001, < 0.001, respectively). There was no statistically significant difference between FDG and FAPI SUVmax values in osteoblastic bone metastases (P = 0.26).ConclusionIt has been shown that ⁶⁸Ga-FAPI-04 PET/CT is superior to ¹⁸F-FDG PET/CT in detecting metastatic bone disease and may have more clinical impact on disease management.     

Combination of [68Ga]Ga-PSMA PET/CT and [18F]FDG PET/CT in demonstrating dedifferentiation in castration-resistant prostate cancer

Aim of the studyIn this study, we aimed to determine the factors affecting increased glucose metabolism, which is one of the dedifferentiation mechanisms, by using [¹⁸F]FDG and [⁶⁸Ga]Ga-PSMA PET/CT in patients with castration-resistant prostate cancer (CRPC).Materials and methodNinety-three patients with CRPC were included in the study. Gleason score (GS), and total PSA and free PSA levels of the patients were recorded. Patient- and organ-based evaluations were performed according to the lesion uptakes as follows: score 0: PSMA (-) FDG (-), score 1: PSMA (+) FDG (-), score 2: PSMA (+) FDG (+) (FDG < PSMA), score 3: PSMA (+) FDG (+) (FDG = PSMA), score 4: PSMA (+) FDG (+) (FDG > PSMA), and score 5: PSMA (-) FDG (+). scores 1 and 2 were classified as group 1, and scores 3 to 5 were classified as group 2.ResultsThe median age of our patients was 70 (51–88) years. Eighty-eight patients (94.6%) were PSMA-positive, 78 patients (83.8%) were FDG-positive, and 89 patients (95.6%) were or PSMA or FDG positive. When the two groups were compared in terms of patient-based parameters, the median age and GS were found to be significantly higher in group 2. ROC analyses revealed that age and GS were significant in predicting group 2.ConclusionSince glucose metabolism can increase in CRPC patients with advanced age and high GS, we recommend combining [¹⁸F]FDG PET/CT with [⁶⁸Ga]Ga-PSMA PET/CT in routine clinical practice in order to identify this patient subset and refer them to additional therapies.     

Tomographie par émission de positons au F-fluorodeoxyglucose dans la mise en évidence de la maladie veineuse thromboembolique

Purpose

Association of venous thromboembolism (VTE) and inflammation reported in the literature may allow the use of FDG PET/CT in the detection of thrombotic process. Published studies remain limited and contradictory. The aim was, therefore, to evaluate the performance of FDG PET/CT for the detection of VTE.

Patients and methods

Patients included in a prospective study evaluating FDG PET/CT for the detection of malignancy in patients with idiopathic VTE were analysed (MVTEP, PHRC 2008). PET/CT images were interpreted initially without and then retrospectively with knowledge of VTE locations.

Results

Hundred and fourteen patients were included in MVTEP study from March 13th 2009 to July 1st 2010. Forty-six patients (median age: 74 years [20-87], 27 males, 19 females) were analysed. No abnormal uptake was initially reported in pulmonary vessels. The retrospective analysis of pulmonary embolism locations did not demonstrate any significant difference in FDG uptake between embolic sites and controlateral vessels (P = 0.883). Initial analysis of lower limbs vessels demonstrated sensitivity and specificity of PET/CT for deep venous thrombosis (DVT) diagnosis of 15 and 99%. The metabolic activity of DVT was significantly higher than the activity of controlateral vessels (P < 0.005) but without showing any significant SUV threshold for DVT diagnosis.

Conclusion

In conclusion, there is insufficient evidence to suggest that FDG PET/CT could be accurate in detection of VTE. These results need to be completed in a larger study with shorter delay between VTE and FDG PET/CT.     

TEP au 18-FDG et carcinose péritonéale d’origine ovarienne : valeurs diagnostique et pronostique avant chimio-hyperthermie intra-péritonéale (CHIP)

AimEvaluate 18-FDG PET/CT diagnostic and prognostic value before HIPEC.Materials and methodsThis retrospective monocentric study included 38 patients with recurrent (n = 27) or primary (n = 11) ovarian cancer who were blinded reviewed for the presence of peritoneal lesions on PET/CT before HIPEC treatment. The results were compared to surgical and histopathological findings, and to survival curves.ResultsThirty-two patients had peritoneal carcinomatosis based on surgical and histopathological findings, and 19 based on PET. There was no suspicious site of abnormal FGD uptake in the supradiaphragmatic regions. The sensitivity and specificity were respectively 56.2 and 100%. Among the 14 false negative patients, 11 had infracentimetric peritoneal implants, and most of them (n = 13) had chemotherapy before HIPEC. There was significantly more patients treated by chemotherapy in the negative PET group (P = 0.02). Even if the event rate observed was higher in the positive PET group for both event free and overall survival (respectively 68% vs. 64% and 26.3% vs. 17.6%), no significant difference was observed using the survival curves (respectively P = 0.62 and 0.59).ConclusionFDG PET/CT before HIPEC showed excellent specificity and lower sensitivity, due to small peritoneal implants and probably to chemotherapy before HIPEC. No significant prognostic value of FDG PET was observed in our study. FDG PET could be considered as a useful tool for detecting distant metastasis with an impact on therapeutic management.     

Intégration des critères métaboliques de la TEP au 18FDG pour le choix des lésions cibles en imagerie onco-hématologique

IntroductionMalignant lymphoma is a heterogeneous and widespread disease. The morphological response assessment is currently based on the choice of target lesions at baseline, defined by size criteria on enhanced CT (eCT). FDG PET/CT is now commonly used at staging and the aim of this study was to evaluate the relevance of using metabolic criteria rather than size criteria to define the target lesions.Patients and methodsFifty-nine patients with aggressive lymphoma were retrospectively included. Target lesions were chosen by two radiologists on eCT and by two nuclear physicians on PET/CT. Response assessment, based on the sum of the products of the greatest diameters of up to six target lesions chosen either by size or metabolic criteria, was computed and compared to a clinical gold standard (GS) for each patient. Interobserver agreement and comparison to the GS were assessed with kappa (κ) and intraclass correlation (ICC) statistics.ResultsThe spatial distribution of target nodal areas was equivalent among eCT and PET/CT readers with a maximum of target lesions in cervical and mediastinal areas. Choosing with PET/CT led to significant heterogeneity in the size of target lesions when compared with eCT alone (P = 0.03). Interobserver agreement for quantifying the response rate was equivalent in both groups. However, there was a greater correlation to the response of the GS when using PET/CT to target the patient (κ = 0.64 vs. 0.47) and an increased rate of complete responses.ConclusionsMetabolic criteria can replace current size criteria to define target lesions on FDG PET/CT. The morphological response rate appears accurate with an increased rate of complete responses after therapy and a better correlation to the haematological standard of reference.     

Comparaison IRM de diffusion corps entier et TEP/TDM au 18FDG dans le diagnostic de myélome symptomatique

IntroductionOur work aims to compare whole-body diffusion MRI (DWMRI) and ¹⁸FDG PET/CT in the diagnosis of symptomatic myeloma.Patients and methodFrom November 2008 till May 2010, 19 patients were investigated by DWMRI and by ¹⁸FDG PET/CT. The patients were classified according to the criteria of the International Myeloma Working Group in eight non-symptomatic myelomas and 11 symptomatic myelomas. The sensitivity and the specificity of two methods of imaging were studied by retaining the presence or the absence of a diffuse infiltration (ID), focal lesions (FL), or both parameters (FL + ID), in both modalities of imaging. We compared the concordance between two techniques for every patient by using these signs using a weighted kappa test.ResultsThe performances of both modalities seem comparable, with superior diagnostic performances for the FL (Se = 100% and Sp = 75% in DWMRI and Se = 91% and Sp = 75% for ¹⁸FDG PET/CT). By combining both parameters, the ¹⁸FDG PET/CT seems more specific, but the sensitivity is comparable in both modalities (Se = 100% in MRI and Se = 100% in ¹⁸FDG PET/CT; Sp = 37% in DWMRI and Sp = 62% for ¹⁸FDG PET/CT). The concordance between both techniques is better by taking into account the FL than the other parameters (weighted kappa = 0.61 for FL, 0.5 for the FL + ID and 0.16 for ID alone).ConclusionDiagnostic performances of whole-body diffusion MRI and ¹⁸FDG PET/CT seem equivalent, but concordance between both techniques is imperfect. Further studies are necessary to understand this discrepancy.     

La TEP/TDM au FDG a-t-elle un impact dans la prise en charge des patients atteints d’un cancer du canal anal ?

PurposeTo evaluate the impact of FDG PET/CT on the management of patients referred for the staging and/or the follow-up of anal carcinoma, and PET/CT on patient management.Patients and methodsWe included patients referred to our department for anal carcinoma whose therapeutic management was evaluable thanks to follow-up data during at least 6 months.ResultsData of 44 patients were analysed: 22 had PET/CT for initial staging and 36 during follow-up. PET/CT had impact in nine patients out of 44 (20%) and it was relevant in eight of them.ConclusionFDG PET/CT is an accurate imaging modality in anal cancer, its impact on patient management is more obvious when persistence or recurrence of disease is suspected.     

Signification d’une hyperfixation prostatique du fluorodésoxyglucose (18F) chez un patient sans antécédent de cancer de la prostate. Cas cliniques,revue et méta-analyse de la littérature

FDG is not suited for the detection of prostate cancer. However, high prostate uptake demonstrated unexpectedly on FDG PET/CT requested for another indication may lead to the detection of prostate cancer, although a non-malignant origin is more common. We report 4 cases of prostate incidentaloma detected on high FDG prostate uptake, corresponding to 4 typical images and circumstances: diffuse uptake, focal uptake with various levels of SUV_max and of serum PSA level assayed on the basis of PET/CT result. We performed a meta-analysis of the 6 series in the literature currently reporting characterisation of prostate incidentalomas, in a total of 47,935 FDG PET, the average frequency of this incidentaloma is 1.5%; it was characterised in 68% of cases, corresponding to cancer in 16% of characterised cases, adenocarcinoma in 75 cases/78. There was no correlation between the Gleason score and the SUV_max; adenocarcinoma Gleason = 6 can be unexpectedly detected with FDG. Among the risk factors for malignancy, there is a SUV_max > 3, a peripheral location within the prostate and no calcification in the hypermetabolic area. Prostate biopsy may be indicated only in case the management of the patient would be modified if prostate cancer is confirmed; it is prompted in the case of clear elevation of serum PSA level, but also when serum PSA level is normal but there is one or several risk factors on FDG PET/CT images.     

Impact de la TEP/TDM au 18F-FDG dans la prise en charge des patients atteints de cancer thyroïdien différencié

Aim¹⁸F-FDG PET/CT by combining both metabolic and anatomical informations has proven to be an effective modality for detecting many types of cancer. Some differentiated forms of cancer like differentiated thyroid carcinoma (DTC) are less FDG avid and thus less easily detectable. Nevertheless ¹⁸F-FDG PET/CT has been proved useful in DTC especially in case of suspected recurrent disease with negative whole-body radioiodine scintigraphy (¹³¹I WBS) and elevated thyroglobulin (Tg) or thyroglobulin autoantibodies (AbTg) levels. Impact on clinical management after ¹⁸F-FDG PET/CT examinations has been analyzed in patients with suspected recurrent DTC in this retrospective study.MethodologyFifty-five ¹⁸F-FDG PET/CT were performed in 45 patients with suspected recurrent or residual disease either because of elevated Tg/AbTg levels (n = 45) or uncertain conventional imaging (n = 10) including ¹³¹I WBS, cervical echography and CT scan if necessary. ¹⁸F-FDG PET/CT results were compared with histopatology and/or clinical follow-up with evaluation of impact on clinical management.ResultsTwenty-nine exams were positive (53 %). There were 20 true-positive (TP) (14 locoregional relapses and six with distant metastases) and nine false-positive (FP) (all cervical). SUV_max median values of hypermetabolic foci were significantly higher in TP (5.1) than in FP (2.8). Overall, 20 (36 %) ¹⁸F-FDG PET/CT directly affected clinical management resulting in 13 (65 %) new surgical operations. Sensitivity, specificity, predictive positive value, predictive negative value and accuracy of ¹⁸F-FDG PET/CT were estimated for the whole group (respectively 83 %, 71 %, 69 %, 85 % and 76 %) and for two subgroups depending on Tg level (less or more than 1.2 ng/mL).Discussion and conclusion¹⁸F-FDG PET/CT is a powerful and useful tool in patients with suspected DTC recurrence or residual disease and should be systematically performed when basal Tg level is above 1.2 ng/mL. Thanks to given anatomical informations it can guide surgical re-operation.     

Prognostic Value of SUVmax Measured by Pretreatment Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Patients with Ewing Sarcoma

AimThe aim of this retrospective study was to determine whether glucose metabolism assessed by using Fluorine-18 (F-18) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) provides prognostic information independent of established prognostic factors in patients with Ewing sarcoma.MethodsWe retrospectively reviewed the medical records of 34 patients (men, 19; women, 15; mean age, 14.5 ± 9.7 years) with pathologically proven Ewing sarcoma. They had undergone F-18 FDG PET/CT as part of a pretreatment workup between September 2006 and April 2012. In this analysis, patients were classified by age, sex, initial location, size, and maximum standardized uptake value (SUVmax). The relationship between FDG uptake and survival was analyzed using the Kaplan-Meier method with the log-rank test and Cox’s proportional hazards regression model.ResultsThe median survival time for all 34 subjects was 999 days and the median SUV by using PET/CT was 5.8 (range, 2–18.1). Patients with a SUVmax ≤ 5.8 survived significantly longer than those with a SUVmax > 5.8 (median survival time, 1265 vs. 656 days; p = 0.002). Survival was also found to be significantly related to age (p = 0.024), size (p = 0.03), and initial tumor location (p = 0.036). Multivariate analysis revealed that a higher SUVmax (p = 0.003; confidence interval [CI], 3.63–508.26; hazard ratio [HR], 42.98), older age (p = 0.023; CI, 1.34–54.80; HR, 8.59), and higher stage (p = 0.03; CI, 1.21–43.95; HR, 7.3) were associated with worse overall survival.ConclusionsSUVmax measured by pretreatment F-18-FDG PET/CT can predict overall survival in patients with Ewing sarcoma.     

Comparaison de l’IRM de diffusion et de la TEP/TDM au FDG dans le bilan des lymphomes

PurposeDiffusion weighted MRI (DW-MRI) sequences appear as a promising functional technique supplementary to morphologic MRI for oncology purposes. We evaluated the results of DW-MRI for the staging of lymphomas, compared to FDG PET/CT.MethodsTwenty-seven patients with lymphoma referred for FDG PET/CT (initial staging, relapse or treatment evaluation) were prospectively included. They underwent MRI including free breathing DW and T2 weighted imaging. Lymph node areas and organs involvement were listed for each modality and compared using Cohen's kappa (κ) test. MRI performances were evaluated using FDG PET as the gold standard. The results of PET and MRI were compared (with respect to the final staging by the haematologist).ResultsRegarding the lymph nodes, 154 involved areas were detected by MRI out of the 184 detected by PET, that is an excellent concordance (κ = 0.87), sensitivity of 0.84 and specificity of 1. Concordance and sensitivity were inferior for extranodal disease (notably bone lesions) with 27 lesions detected by MRI out of the 40 viewed with PET. Regarding pre-treatment evaluation, two patients were understaged both with PET and MRI (bone marrow involvement); assessment of stage was concordant for both modalities in 18 patients out of 21.ConclusionsPerformance of MRI including DW images was close to that of FDG PET/CT for lymph node areas involvement. Further studies are needed to assess its sensitivity for extranodal lesions, and its accuracy for determining the stage of the disease.     

Non-rigid registration of serial dedicated breast CT,longitudinal dedicated breast CT and PET/CT images using the diffeomorphic demons method

Rationale and objectivesDedicated breast CT and PET/CT scanners provide detailed 3D anatomical and functional imaging data sets and are currently being investigated for applications in breast cancer management such as diagnosis, monitoring response to therapy and radiation therapy planning. Our objective was to evaluate the performance of the diffeomorphic demons (DD) non-rigid image registration method to spatially align 3D serial (pre- and post-contrast) dedicated breast computed tomography (CT), and longitudinally-acquired dedicated 3D breast CT and positron emission tomography (PET)/CT images.MethodsThe algorithmic parameters of the DD method were optimized for the alignment of dedicated breast CT images using training data and fixed. The performance of the method for image alignment was quantitatively evaluated using three separate data sets; (1) serial breast CT pre- and post-contrast images of 20 women, (2) breast CT images of 20 women acquired before and after repositioning the subject on the scanner, and (3) dedicated breast PET/CT images of 7 women undergoing neo-adjuvant chemotherapy acquired pre-treatment and after 1 cycle of therapy.ResultsThe DD registration method outperformed no registration (p < 0.001) and conventional affine registration (p ≤ 0.002) for serial and longitudinal breast CT and PET/CT image alignment. In spite of the large size of the imaging data, the computational cost of the DD method was found to be reasonable (3–5 min).ConclusionsCo-registration of dedicated breast CT and PET/CT images can be performed rapidly and reliably using the DD method. This is the first study evaluating the DD registration method for the alignment of dedicated breast CT and PET/CT images.     

Découverte fortuite de fixations colorectales focales du FDG en TEP/TDM : corrélation aux données de la coloscopie

PurposeFDG-PET is an established tool for the diagnosis of recurrent or metastatic colorectal carcinoma. Several case series suggest that FDG-PET often detects incidental adenomatous polyps or colorectal adenocarcinomas. The aim of this study was to correlate unexpected colorectal foci of FDG uptake to pathology findings after systematic colonoscopy.Patients and methodsWe reviewed the records of 3541 patients who underwent FDG PET/CT in our institution over a 30-month period for the assessment of a known or suspected malignancy. In 85 of them, incidental, nodular shaped and well-circumscribed foci of abnormal uptake were identified in the area of the colon or rectum. Patients with segmental or diffuse abnormal colorectal uptake were excluded, as well as patients with known benign or malignant colorectal disease. Colonoscopy and complete pathology report was available in 29 patients. Maximal standardized uptake value (SUV_max) was measured in all lesions.ResultsUnexpected colorectal foci of FDG uptake were associated with colonoscopic abnormalities in 23 patients (true positive rate: 79 %). Adenocarcinomas were found in six patients (SUV_max = 7.3 ± 2.6), tubulous adenomas in four patients (SUV_max = 7.3 ± 4.9) and tubulovillous adenomas in 12 patients (SUV_max = 4.2 ± 1.1). Hyperplasic polyps with no sign of dysplasia were found in the last patient (SUV_max = 3.3). Concomitant CT abnormalities were found on PET/CT fusion in eight patients and consisted of wall thickening (n = 5) or nodular mass (n = 3). Conversely, PET was falsely positive in six patients (21 %), with no concomitant CT abnormalities and no abnormal findings at endoscopy (SUV_max = 6.2 ± 2.8, no significant difference with true positive lesions).ConclusionOur findings emphasize the need to perform a colonoscopy in front of incidental nodular colorectal foci of FDG uptake because malignant or pre-malignant neoplasms, which are not clinically apparent, are found in more than three-quarter of cases.     

Valeur pronostique de la TEP/TDM dans le bilan initial du cancer du col utérin : SUVmax de la tumeur primitive et stadification ganglionnaire

PurposeWe investigated the prognostic significance of F-18 fluorodeoxyglucose (FDG) uptake measured as maximum Standardized Uptake Value (SUV_max) in primary tumor by positron emission tomography/computed tomography (PET/CT) in cervical cancer. The secondary objective was to determine the accuracy of the PET/CT for detecting pelvic lymph node (PLN) and para-aortic lymph node (PALN) metastases.MethodsThis retrospective study included 49 consecutive patients with stage IB1 to IVB cervical cancer. Univariate analysis was performed to determine the relationships between SUV_max value and pathological prognostics factors. Survival was estimated by Kaplan-Meier method. The gold standard of LN metastases was histologic.ResultsA significant difference in SUV_max was observed between stage I and stage II, stage I and stage IV and tumor size ≤ 4 cm and > 4 cm (P = 0.0001). There was a significant correlation between the SUV_max and tumor maximal size (r = 0.597) (P < 0.0001). PLN metastasis was found to be predictive of progression-free survival (P = 0.0007). The negative predictive value (NPV) of the PET/CT for PALN was 100% for locally advanced cervical carcinoma in 24 patients. The specificity and NPV of the PET/CT for PLN in eight early-stage cervical cancer were 100% and 87.5% (7/8) respectively. The PET/CT false-negative PLN measured less than 2 mm.ConclusionOur results demonstrate a correlation between SUV_max and tumor maximal size, which represents an indicator of tumor aggressiveness. PET/CT is effective to predict the absence of PALN in locally advanced cervical carcinoma. PET/CT is not sufficient to predict PLN in early-stage cancer without lymphadenectomy.     

Analyse texturale en TEP au FDG des cancers pulmonaires non à petites cellules de stade localement avancé : valeur pronostique de l’entropie

IntroductionIn the current context of personalized medicine, textural analysis promises to be an accurate approach of cancer prognosis. The lack of standardization and the multitude of textural indices limited radiomics studies reproducibility as an obstacle of introduction of textual analysis into clinical practice. Our study assessed the prognostic value of entropy in 18F-FDG PET/CT in locally advanced non-small cell lung cancer (NSCLC).MethodPatients who performed 18F-FDG PET/CT for lung cancer staging between September 2015 and April 2017 in 2 hospitals were included for conventional and textural PET parameters extraction. A retrospective analysis of patient was performed over 24 months to determine the progression-free survival and overall survival.ResultsForty-two patients were included. Progression-free survival was significantly correlated with entropy on multivariate regression (cut-off at 8.4) with a hazard ratio of 3.04 (95 % CI 1.13–8.16) (P = 0.03), as MTV (P < 0.001). Neither conventional PET parameters nor entropy was a significant association with overall survival.ConclusionThese results confirmed the external validity and robustness of FDG PET entropy as an independent prognostic factor of progression-free survival in patients with locally advanced NSCLC, in addition to Conventional PET.     

La fluorocholine(18F) a une utilité clinique dans le cancer de la prostate et le carcinome hépatocellulaire… parfois chez le même malade

Case reportIn order to stage hepatocellular carcinoma (HCC), a patient was referred to PET/CT using fluorodeoxyglucose(18F) (FDG) and, if necessary, fluorocholine(18F) (FCH). HCC was proven by biopsy of a hepatic mass discovered on CT performed for a biological recurrence of prostate cancer.ResultFDG PET/CT did not show any anomaly. FCH PET/CT was thus performed and showed various foci: the hepatic mass, a large abdominal adenopathy and an unexpected subcentimetre lung nodule. The diagnostic uncertainty mostly concerned this lung nodule which was biopsied and consisted of a metastasis of the prostate cancer. Due to the presence of two metastatic cancers, the patient's management was altered, with chemotherapy for the HCC and hormone therapy for the prostate cancer.ConclusionSeveral types of cancer take-up fluorocholine(18F), which is a powerful tool to detect metastases, in particular in case of rising levels of marker with a negative FDG PET/CT. Even when FDG PET/CT is positive, FCH may reveal unexpected foci with other metabolic characteristics, although it is not specific of a given primary cancer, as well as FDG. For staging of HCC, we thus recommend to perform PET/CT with both tracers.