18F-sodium fluoride PET/CT indications

¹⁸F-sodium fluoride uptake mechanism is based on the fluoride ion exchange, with a hydroxyl group of the hydroxyapatite being at the surface of the bone crystals and thus forming fluorapatite, especially at sites with a high rate of bone remodeling. ¹⁸F-fluoride shows a lower protein binding and faster plasma clearance with respect to ^99mTc-diphosphonates (twice increased bone uptake). The adult dose range is 185–370 MBq, whereas in children it is advisable to adjust dose (0.057 mCi/kg). The acquisition time of the ¹⁸F-fluoride PET study is similar to that of ¹⁸F-FDG one (60 ± 30 minutes). The CT is required for attenuation correction (low amperage 30 mAs) but also allows artifact reduction and quantification. ¹⁸F-fluoride PET shows high sensitivity for detection of bone metastases, affecting its specificity. However, CT addition may increase specificity, resulting in a high accuracy of ¹⁸F-fluoride PET/CT. Given its uptake mechanism, its sensitivity is higher for mixed and blastic metastases rather than for lytic ones. Multiple studies have shown that the sensitivity of the ¹⁸F-fluoride is higher than bone scan, including whole-body bone SPECT. However, ¹⁸F-fluoride PET/CT should find their real indications in the current algorithms of clinical practice.     

Increased Arterial PET/CT 18F-Fluorodeoxyglucose Uptake in Obese and Overweight Patients

ObjectivesWe aimed to investigate the association between BMI and early atherosclerotic activity in cancer patients. We also compared the inflammatory and macroscopic calcification processes of atherosclerosis in the aortic segments and large arteries by ¹⁸F-FDG PET/CT of between normal and high BMI patients.MethodsWe conducted a retrospective review of cancer patients presented to our institution within the period between February and May 2018. Patients were classified according to their BMI into two groups: normal BMI group and high BMI group. Data of average SUVmax and SUVmean for four segments of the aorta, common iliac arteries, and femoral arteries were estimated and compared between both groups. Moreover, the macroscopic calcification on CT images for each vascular section was also reported.ResultsNinety-eight patients were classified into two groups: normal BMI group (n = 52; 53.1%), and high BMI group (n = 46; 46.9%). Average SUVmax was significantly higher in obese participants in all arterial segments (P < 0.05). However, the SUVmean was significantly higher in obese patients in only three arterial segments aortic arch, left femoral artery and descending thoracic aorta (P < 0.05).Moreover, the differences between the two study groups in terms of the frequency of macroscopic calcifications were not statistically significant for all vascular segments. BMI positively correlated with SUVmax and SUVmean of the vascular segments (r value from 0,219 to 0,575/p value between 0,023 and 0,0001).ConclusionsFluorine-18-FDG PET/CT imaging revealed that patients with high BMI have more accelerated atherosclerotic inflammatory process in their major vessels compared to their age-matched controls with normal BMI. Future studies should assess the associated between these findings and the cardiovascular events in the long term.     

Dual-time-point PET/CT study protocol can improve the larynx cancer diagnosis

AimTo evaluate whether the sequential dual-time-point fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (DTP 18F-FDG PET/CT) study improves the differential diagnosis in the larynx.BackgroundIn some cases, the clinical and metabolic similarity of laryngitis and larynx cancer make differential diagnostics difficult when performing standard 18F-FDG PET/CT examinations; therefore, an additional study protocol performance seems to be of reasonable value.Materials and methods90 patients (mean age: 61 ± 11 years, range: 41–84 years): 23 women (mean age: 63 ± 10 years, range: 51–84 years) and 67 men (mean age: 61 ± 11 years, range: 41–80 years) underwent delayed 18F-FDG PET/CT examinations at 60 and 90 min post intravenous injection (p.i.) of the radiopharmaceutical 18F-FDG. We compared the metabolic activity of 90 structures divided into following groups: normal larynx (30 patients), laryngitis (30 lesions) and larynx cancer (30 tumors) with maximal and mean standardized uptake value (SUVmax, SUVmean) and the retention index (RI-SUVmax). We used the receiver operating characteristics (ROC) curve to evaluate the SUVmax cut-off values.ResultsThe SUVmax cut-off value at 60 and 90 min p.i. of 2.3 (sensitivity/specificity: 96.4%/100%) and 2.4 (94.2%/100%), respectively, distinguished normal and abnormal metabolic activity in the larynx. When laryngitis and tumors were compared, the SUVmax cut-off values obtained after initial and delayed imaging were 3.6 (87.5%/52.0%) and 6.1 (58.3%/84%), respectively. The RI-SUVmax of 1.3% (71.4%/88.1%) suggested abnormality, while RI-SUVmax of 6.6%, malignant etiology (75.0%/80.0%).ConclusionsIn this study, the sequential DTP scanning protocol improved the sensitivity and specificity of the PET/CT method in terms of differential diagnosis within the larynx.     

Intérêt pronostique et prédictif de la TEP-TDM au 18F-FDG au bilan initial des mélanomes de stade IIIB-C-D et IV avant traitement par anti-PD-1

PurposeThe advent of immunotherapy by checkpoint inhibitor has profoundly changed the prognosis of patients with metastatic melanoma. The objective of our study was to evaluate the prognostic and predictive performance of 18F-FDG PET/CT of the initial extension assessment of stage IIIB-C-D and IV melanomas.MethodsWe retrospectively included 57 patients who had 18F-FDG PET/CT prior to the introduction of anti-PD-1 immunotherapy. The parameters extracted were SUVmax, SUV peak, MTV and TLG of the lesion with highest uptake (MTV LM, TLG LM), as well as MTV total and TLG total, obtained by adaptive segmentation. The18F-FDG PET/CT were dichotomized using the optimal threshold measured according to the area under the curve in the ROC (Receiver Operation Characteristic) curves. These parameters were evaluated using a Cox model. Overall survival and progression-free survival analyses were performed using the Kaplan Meier model.ResultsThe median follow-up was 25.4 months, 38 patients had progressed or recurred, and 20 patients had died. TLG LM > 132.59 (P = 0.0011), MTV total > 12 cm³ (P = 0.0139), and TLG > 94.17 (P = 0.0084) were significantly associated with a shorter progression-free survival. TLG LM > 145.92 (P = 0.0062), MTV total > 10.16 cm³ (P = 0.0051), and a metastatic spread > 2 organs (P = 0.0001) were associated with a shorter overall survival.ConclusionWe confirm the potential prognostic interest of PET-TDM at 18FDG before immunotherapy of stage IIIB-C-D and IV melanomas on progression-free survival and overall survival. The combination of these metabolic markers reflecting tumor burden with clinical and biological prognostic factors could allow early identification of patients at high risk of anti-PD-1 failure.     

Performances de la TEP au 18F-FDG dans la caractérisation initiale de la lésion primitive du cancer du sein

Objective¹⁸F-FDG PET/CT is for the moment not recommended for stage T of the TNM classification of breast cancer. The aim of our study was to evaluate the performance of ¹⁸F-FDG PET/CT in the initial staging of breast tumors. Tumor size, skin involvement and inflammation as well as the relationship between primary tumor maximum standardized uptake value (SUVmax) and histopathological grade (SBR), molecular tumor subtypes (luminal A and B, Her2 enriched, triple negative), estrogen receptors (ER), progesterone receptors (PR) and focality were evaluated.MethodsHistological reports of patients operated for breast cancer, without neoadjuvant chemotherapy, were compared to preoperative ¹⁸F-FDG PET/CT.ResultsSeventy-four patients who underwent surgery in 2016 were included. ¹⁸F-FDG PET/CT was able to visualize primary tumors in 91% and to correctly classify the T stage of the TNM classification in 81% of the cases, to detect multifocality in 73% and cutaneous and inflammatory breast cancers in 100%. The uptake intensity of ¹⁸F-FDG (SUVmax) was significantly correlated with histo-prognostic factors such as SBR grade (P = 0.02), lack of expression of estrogen receptors (ER) (P = 0.01) and progesterone (PR) (P = 0.02), positive HER2 status (P = 0.01) or triple negative subtype tumors (P = 0.02).Conclusion¹⁸F-FDG PET/CT provides relevant elements for local assessment, in particular, tumor focality and inflammatory character in addition to ensuring the regional and extension assessment.     

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.     

No diagnostic impact of routinely use of respiratory gating to characterize lung nodules with 18F-FDG PET/CT

Purpose

To evaluate diagnostic impact of routinely use of respiratory gated (RG) ¹⁸FDG PET/CT to distinguish benign and malignant lung nodules.

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.     

Quantification and monitoring of PET/CT data in multicentre trials: The Swiss SAKK 56/07 trial experience

AimTo outline the importance of continuous monitoring of quantitative positron emission tomography (PET) data in multicentre trials to minimize quantitative bias in longitudinal intra-patient PET studies in light of the multicentre SAKK 56/07 experience in quantification and monitoring ¹⁸F-FDG PET/CT data.Patients and methodsWe collected 64 uniform phantom ¹⁸F-FDG PET acquisitions periodically at the enrolling centres (12 European institutions). A core-laboratory analysed them for standard uptake value (SUV) accuracy (desired 1.00 ± 10%) and acceptable image noise was defined by a coefficient of variation (COV) less than 15%. In total, 151 patients ¹⁸F-FDG PET acquisitions (baseline and follow-up) were also collected and analysed to verify longitudinal coherence of main acquisition/reconstruction parameters (DICOM tags verification) and patient preparation, in particular the uptake time (desired uptake time [UT] = 60 ± 10 min).ResultsUniform phantom PET acquisition satisfied the inclusion criteria in 58/64 (89%) examinations. All PET scanner exhibited comparable SUV quantification, but we found large dispersion in terms of noise, with COV ranging 3–15%. Only 1 phantom PET acquisition was out of range with COV = 21.5%. Patient data exhibited important variation in uptake time with UT = 65 ± 10 min (mean ± SD), with only 111/151 (74%) patients’ examinations satisfying inclusion criteria while 26% were out of range.ConclusionsRegular monitoring of PET data in multicentre trials is capital to ensure longitudinal intra-patient PET data consistence and minimize quantitative bias while it helps to spread the culture of quality in participating centre. Recent EARL (EANM Research Ltd) standardization and unification of procedures is a welcome step in this direction.     

Intérêt pronostique et prédictif de la TEP-TDM au 18F-FDG chez les patients atteints de léiomyosarcomes de stades avancés

PurposeAssessment of early therapeutic response is essential to guide therapeutic management in patients with advanced leiomyosarcoma (LMS). We compared the predictive values of various 18F-FDG PET-CT-derived metabolic parameters, SUVmax, SUVpeak, metabolic tumor volume (MTV) and total lesion glycolysis (TLG).MethodsA total of 64 patients with LMS who underwent FDG PET/CT before and 6 weeks after the initiation of treatment were retrospectively analyzed. We determined SUVmax, SUVpeak, MTV, and TLG by segmentation to compare their predictive value for 9-month progression-free survival and overall survival. These parameters were dichotomized using the optimal threshold according to the area under the ROC (Receiver Operation Characteristic) curve and evaluated using a Cox model. Overall and progression-free survival analyses were performed using the Kaplan Meier model.ResultsSUVmax showed greater accuracy than TLG or MTV in ROC analysis (area under the curve, AUC, 0.680, 0.677, and 0.675, respectively). The cutoff values derived from the AUC data were SUVmax 4.7, TLG 37.46, and MTV 25 cm³. After dichotomization by threshold values, MTV was the most significant predictor compared with SUVmax and TLG (P = 0.000165, P = 0.007, and P = 0.001, respectively). In early therapeutic evaluation at 6 weeks, delta SUVpeak and PERCIST metabolic response were significantly correlated with progression-free survival (P = 0.008 and 0.035, respectively).ConclusionBaseline SUVmax, MTV and TGL were predictive of overall survival, delta SUVpeak and PERCIST response obtained by functional imaging in early therapeutic evaluation were significantly correlated with progression-free survival in advanced leiomyosarcoma patients.     

Apport d’un nouveau score visuel en TEP/TDM au 18Fluorodeoxyglucose (18FDG) lors des récidives ganglionnaires de cancer ORL après traitement initial

New visual score in PET/CT 18Fluorodeoxyglucose (¹⁸FDG) to evaluate lymph node recurrence of head and neck cancer after initial treatment. Neck dissection for node recurrence of head and neck cancer is known for important morbidity after initial radiation therapy. ¹⁸FDG PET/CT in this situation looks interesting but needs standardized interpretation. Our objective was to develop a PET/CT interpretation method in suspicious locoregional head and neck recurrence. Twenty-seven patients with suspicious lymph node recurrence after initial radiation ± chemotherapy for head and neck cancer were retrospectively included. ¹⁸FDG PET/CT was performed before neck dissection and histological data. Initial PET records, binary visual scale, five-point visual scale “Deauville like” and semi-quantitative index were assessed by 2 reviewers. A lymph node recurrence was confirmed in 19 patients (70%) based on histological results. PET records analysis found 6 false positive (FP), 2 true negative (TN) and 19 true positive (TP), with a sensibility (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of 100%, 25%, 76% and 100%, respectively. Binary visual scale reclassified 1/6 FP. “Deauville like” criteria, reclassified 4/6 FP with the first reviewer (P < 0.001) and 5/6 with the second (P < 0.002), improving Sp and PPV of 66% and 95%, respectively. Kappa concordance coefficient for “Deauville like” scale was 0.88. Semi-quantitative index like SUVmax, SUVmean, SUVpeak, MTV, TLG and SAM showed no statistical value. Those preliminary results warrant a standardized visual scale, particularly the “Deauville like” criteria for ¹⁸FDG PET/CT interpretation in suspected lymph node recurrence of head and neck cancer.     

Étude rétrospective des conséquences de l’administration d’une préparation de FDG contenant de 5 % à 10 % de fluorure (18F) libre sur l’imagerie TEP/TDM de l’os sain et des foyers osseux pathologiques. Comparaison avec un groupe apparié de patients ayant reçu une préparation de FDG contenant moins de 5 % de fluorure (18F) libre

Following administration in January 2010 of a commercial preparation of FDG containing between 5 and 10% of fluoride (18F), our aim was to evaluate by means of a retrospective study the consequences of this content of free ¹⁸F on the visual and semi-quantitative approaches of the skeletal uptake on PET/CT.MethodsTwo groups of 30 patients (princeps and control) were matched for pathology, age, sex and glycaemia. The group “princeps” received the FDG preparation containing more than 5% of fluoride (18F). All examinations were done according to the standard protocol of FDG PET/CT. The SUVmax was determined in six regions of interest (ROI) in visually normal bone. For pathologic foci, we calculated a ratio of SUVmax between the focus and healthy bone (T/NTR).ResultsThe analysis of normal bone showed, for the spine, a significant difference in SUVmax between the two groups and a significant correlation with the time elapsed between FDG preparation and injection. Concerning the pathologic foci, the T/NTR of two groups were significantly different (P = 0.04).ConclusionWe observed a slight increase of the SUVmax in the healthy spine of patients who received more than 5% of fluoride (18F), explained in part by a longer delay before imaging. The pathologic foci showed a T/NTR lower in the group princeps, however metastases were detected in both groups. Thus, a preparation of FDG close to the end of its shelf life can be used without real consequences for the quality of images for a given patient; in contrast, an accurate quantification of the FDG uptake in the spine requires a minimal proportion of fluoride (18F).     

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.     

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.     

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.     

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.     

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.     

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.     

PET/CT helps to determine treatment duration in patients with resected as well as inoperable alveolar echinococcosis

PurposeThe aim of the study was to determine the role of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) at the end of benzimidazole therapy in alveolar echinococcosis.MethodsA total of 22 patients undergoing PET/CT at the end of benzimidazole therapy were retrospectively registered. Maximum standardized uptake values (SUV_max) were measured in remaining echinococcus manifestations and compared to normal liver tissue. Long-term clinical follow-up was performed, and recorded data included laboratory parameters, clinical information and imaging.ResultsAll patients had no detectable levels of Em-18 antibodies and all echinococcus manifestations were negative on PET/CT, i.e. without focally increased FDG uptake or uptake higher than normal/non-infected liver tissue. All manifestations displayed significantly less FDG-uptake than normal liver tissue, i.e. SUVmax 1.8 (interquartile range (IQR) 1.5–3.5) vs. 3.0 (IQR 2.6–5.7), (p < 0.001). Patients were clinically followed for a median of 9.5 years (IQR 6.5–32.0 years) after their initial diagnosis and for 4.5 years (IQR 3.0–14.0 years) after discontinuation of benzimidazole therapy. No patient showed signs of recurrent infection at the last clinical visit. The 10-year and 20-year freedom from all-cause mortality was 95.0% (95% confidence interval 69.5% - 99.3%), for both. Two events occurred in 292 patient years of follow-up; i.e. two patients (9%) died, one because of pancreatic cancer, the other one because of unknown reasons with no detectable antibody levels.ConclusionsNegative FDG-PET/CT results combined with no detectable levels of Em-18 antibodies may allow for the safe discontinuation of benzimidazole therapy in patients with alveolar echinococcosis.     

Intérêt de la TEP au 18F-FDG préthérapeutique pour prédire la réponse à la radio-immunothérapie dans les lymphomes non hodgkiniens

PurposeRadioimmunotherapy (RIT) is a new treatment option for patients with non-Hodgkin lymphoma (NHL). Response to RIT currently remains difficult to predict using conventional prognostic factors and could be refined using functional imaging. The goal of this work is to evaluate the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in predicting response to yttrium 90-labeled monoclonal antibodies for patients with NHL.MethodThirty-five patients with NHL who had undergone 18F-FDG PET prior to RIT with either 90Y-ibritumomab tiuxetan or 90Y-epratuzumab tetraxetan were included in this retrospective study. Four functional criteria (SUVmax, SUVmean, volume and the product of the volume and the SUVmean-TLG-) were analyzed on a per-lesion basis.ResultsA total of 154 lesions were analysed. The per-lesion analysis revealed significant differences (P < 0.05) between responders and non-responders for several criteria and above all for the SUV.ConclusionOur results suggest a predictive role of 18F-FDG PET prior to RIT by giving a useful indication of the radiosensitivity of the lymphoma.