P.Y. Salaun

External validation of a D-dimer age-adjusted cut-off for the exclusion of pulmonary embolism

External validation of a D-dimer age-adjusted cut-off for the exclusion of pulmonary embolism -

Current incidence of venous thromboembolism and comparison with 1998: a community-based study in Western France

In 1998 we estimated the incidence of venous thromboembolism (VTE) to be 1.8/1,000 per year. The aim of this study was to compare current VTE incidence to that observed in 1998. We prospectively recorded all cases of symptomatic pulmonary embolism (PE) and deep vein thrombosis (DVT) of the lower limbs diagnosed between March 1, 2013 and February 28, 2014 in hospitals and in the community, using the same method and geographic area than in 1998. The 2013 incidence rates of VTE were computed and compared with those of 1998 using age- and sex-specific standardised incidence ratios (SIRs). In 2013, we recorded 576 VTE cases (279 isolated DVT and 297 PE ± DVT). Among 367,911 inhabitants, the overall incidence of VTE was 1.57/1,000 (95 % CI 1.44-1.69). The overall VTE incidence was significantly lower in 2013 as compared with 1998: SIR 0.72 (95 % CI 0.67-0.79) as well as the incidence of isolated DVT: SIR 0.53 (95 % CI 0.47-0.60); conversely, the overall incidence of PE was unchanged: SIR 1.10 (95 % CI, 0.98-1.23) despite an increase in the incidence of isolated PE: SIR 1.29 (95 % CI, 1.10-1.52). In 1998, 4.4 % of PE cases were diagnosed using CTPA as compared with 73.7 % in 2013 (p < 0.001). In conclusion, between 1998 and 2013, the incidence of symptomatic DVT decreased. Conversely, we found no similar reduction in the incidence of symptomatic PE; whether this is due to changes in diagnostic tests and algorithms in the management of suspected PE requires further investigations.

Prognostic evaluation of percentage variation of metabolic tumor burden calculated by dual‐phase 18FDG PET‐CT imaging in patients with head and neck cancer

The purpose of this study was to investigate the prognostic value of percentage variation of metabolic tumor burden in patients with head and neck squamous cell carcinoma (HNSCC).

EORTC PET response criteria are more influenced by reconstruction inconsistencies than PERCIST but both benefit from the EARL harmonization program

BackgroundThis study evaluates the consistency of PET evaluation response criteria in solid tumours (PERCIST) and European Organisation for Research and Treatment of Cancer (EORTC) classification across different reconstruction algorithms and whether aligning standardized uptake values (SUVs) to the European Association of Nuclear Medicine acquisition (EANM)/EARL standards provides more consistent response classification.Materials and methodsBaseline (PET1) and response assessment (PET2) scans in 61 patients with non-small cell lung cancer were acquired in protocols compliant with the EANM guidelines and were reconstructed with point-spread function (PSF) or PSF + time-of-flight (TOF) reconstruction for optimal tumour detection and with a standardized ordered subset expectation maximization (OSEM) reconstruction known to fulfil EANM harmonizing standards. Patients were recruited in three centres. Following reconstruction, EQ.PET, a proprietary software solution was applied to the PSF ± TOF data (PSF ± TOF.EQ) to harmonize SUVs to the EANM standards. The impact of differing reconstructions on PERCIST and EORTC classification was evaluated using standardized uptake values corrected for lean body mass (SUL).ResultsUsing OSEMPET1/OSEMPET2 (standard scenario), responders displayed a reduction of −57.5% ± 23.4 and −63.9% ± 22.4 for SULmax and SULpeak, respectively, while progressing tumours had an increase of +63.4% ± 26.5 and +60.7% ± 19.6 for SULmax and SULpeak respectively. The use of PSF ± TOF reconstruction impacted the classification of tumour response. For example, taking the OSEMPET1/PSF ± TOFPET2 scenario reduced the apparent reduction in SUL in responding tumours (−39.7% ± 31.3 and −55.5% ± 26.3 for SULmax and SULpeak, respectively) but increased the apparent increase in SUL in progressing tumours (+130.0% ± 50.7 and +91.1% ± 39.6 for SULmax and SULpeak, respectively).Consequently, variation in reconstruction methodology (PSF ± TOFPET1/OSEMPET2 or OSEM PET1/PSF ± TOFPET2) led, respectively, to 11/61 (18.0%) and 10/61 (16.4%) PERCIST classification discordances and to 17/61 (28.9%) and 19/61 (31.1%) EORTC classification discordances. An agreement was better for these scenarios with application of the propriety filter, with kappa values of 1.00 and 0.95 compared to 0.75 and 0.77 for PERCIST and kappa values of 0.93 and 0.95 compared to 0.61 and 0.55 for EORTC, respectively.ConclusionPERCIST classification is less sensitive to reconstruction algorithm-dependent variability than EORTC classification but harmonizing SULs within the EARL program is equally effective with either.

Imaging and identification of brown adipose tissue on CT scan.

Two types of adipose tissue (AT) have been described in the field of physiology: white (W) and brown (B) AT. Although WAT is well identified on human imaging, BAT imaging aspect remains to be further explored. The aim of this study was to investigate imaging aspect of BAT and its identification on CT (computed tomography) with iodine‐based contrast media injection. We retrospectively reviewed 464 positron emission tomography (PET)/CT, performed during 21 months on adults younger than 37 years. In 39 cases only, the PET revealed the presence of activated BAT. ROI was placed on both white and brown adipose tissue simultaneously on both PET and CT. Several patients’ characteristics (blood sugar level, gender, age, body mass index) as well as BAT and WAT parameters were assessed. Mean CT densities for WAT and BAT were −99·5 HU versus −32·6, mean SUV were 1·38 versus 13·2 and SUVmax were 1·79 versus 16·57, respectively. We found a statistically significant inverse relation between BMI and BAT density. BAT has a higher density than WAT. In this manner, BAT can be misinterpreted as an infiltration of adipose tissue in neoplasic and inflammatory context. Contrast‐enhanced CT scan allows visualization and identification of BAT.

Correlation between fluorodeoxyglucose hotspots on pretreatment positron emission tomography/CT and preferential sites of local relapse after chemoradiotherapy for head and neck squamous cell carcinoma: Fluorodeoxyglucose hotspots in HNSCC

The potential benefits of 18F‐fluoro‐2‐deoxy‐D‐glucose‐positron emission tomography/CT (FDG‐PET/CT) imaging for radiotherapy (RT) treatment planning of head and neck squamous cell carcinoma (HNSCC) are increasingly being recognized. It has been suggested that intratumoral subvolumes with high FDG avidity (“hotspots”) are potential targets for selected dose escalation. The purposes of this study were to demonstrate that pre‐RT FDG‐PET/CT can identify intratumoral sites at increased risk of local relapse after RT and to determine an optimal threshold to delineate smaller RT target volumes that would facilitate RT dose escalation without impaired tolerance.

Diagnostic performance of 18fluorodesoxyglucose positron emission/computed tomography and magnetic resonance imaging in detecting T1‐T2 head and neck squamous cell carcinoma

The aim of this study was to assess and compare the diagnostic accuracy of 18fluorodesoxyglucose positron emission/computed tomography (FDG‐PET/CT) and magnetic resonance imaging (MRI) to detect T1‐T2 head and neck squamous cell carcinoma (HNSCC).

15. Feasibility and quantitative impact of the use of a FDG PET/CT respiratory gating method using HD Chest without increasing acquisition time, in a daily practice

Introduction Respiratory motion in FDG PET/CT induces blurring images, leading to errors in tumor location and in lesion quantification, especially for lung and upper abdominal lesions. To avoid these artefacts, various respiratory gating methods have been developed and most of current PET/CT scans are equipped. However, these methods are not routinely used especially because they are time-consuming. The aim of the study was to assess the feasibility and the quantitative impact of the use of a respiratory gating method using HD Chest without increasing the acquisition time in all patients referred for a FDG PET/CT in daily practice. Methods All patients referred for whole-body FDG PET/CT were prospectively enrolled. Two sets of images were analysed: standard free-breathing FDG PET/CT images (1mm/s speed, Siemens Biograph mCT flow), and respiratory gating images without changing acquisition time (data were stored in list-mode during standard acquisition, computer automatically kept 35%, 40% and 50% of the counts between 2 determined thresholds). Analysis was done in patients with lung or upper abdominal lesion, other patients were excluded. Contrast to noise ratio (CNR) in each set of gating images was compared to find the best compromise between respiratory blurring correction and count rate. SUVmax, SUVmean, metabolic tumour volume (MTV) were recorded and compared. A 4D reconstruction was performed to measure the displacement of the lesion, and a relative value according to its size was calculated to categorize the results. All results were expressed as mean values of the percentage differences ±standard deviation compared to non-gated data. Results Between October 1 st and December 31 st , 2016, 775 patients were referred to our medicine department for FDG PET/CT examinations. 643 were excluded: technical problem or non compliant patient in 34 cases, 523 patients did not have lung or upper abdominal lesion, in 86 patients respiratory gating images were not usable. Analysis was finally performed on 132 patients (17%). No significant improvement was found in the 40% and 50% reconstructed data regarding to the CNR measure. The 35% reconstructed data were used for the second analysis. SUVmax, SUVmean and MTV changes were respectively 14% ±10, 10% ±7 and −13% ±11 for lesion with a relative displacement less than 80% and respectively 36% ±12, 40% ±10 and −35% ±10 for lesion with a relative displacement more than 80%. Conclusion The use of HD Chest without increasing acquisition time is feasible in daily practice, using 35% reconstructed data and has a quantitative impact for lung or upper abdominal lesion with a significant displacement according to its size.

Quels axes de recherche dans le domaine particulier de la thrombose associée au cancer

The prevention of venous thromboembolism in patients suffering from cancer is currently a major research topic. Antithrombotic prophylaxis may have a clinical benefit in patients undergoing cancer therapy, but no study clearly identifies a group of patients who may benefit from such a prophylaxis, except after oncological abdominal surgery or for patients treated for myeloma. On the other hand, cancer screening procedures, especially in case of idiopathic VTE, remain a diagnostic challenge. Although extensive screening allows earlier detection of malignancies, the impact on survival has not been demonstrated and cost effectiveness remains to be assessed.RésuméLa prévention de la maladie veineuse thromboembolique (MVTE) en cas de cancer est un axe de recherchemajeur et d’actualité. La thromboprophylaxie pourrait avoir un intérêt au cours du traitement des cancers, mais aucune étude ne permet d’identifier clairement un groupe de patients dont la survie serait améliorée par ce traitement, en dehors des chirurgies carcinologiques abdominales et des patients traités pour un myélome. Par ailleurs, le dépistage des cancers en cas de MVTE dite idiopathique est aussi un axe de recherche. Bien qu’un bilan exhaustif permette de découvrir des cancers plus précocement, l’impact de ce dépistage sur la survie n’est pas démontré, et le coût reste à évaluer.

Intérêt de l’imagerie fonctionnelle TEP dans les tumeurs hépatobiliaires primitives malignes

Primarymalignant hepatobiliary tumors include hepatocellular carcinoma, cholangiocarcinoma, and gallbladder cancer. The importance of PET imaging for these malignancies varies depending on the location and the type of the tumor. The value of PET for the detection of primitive hepatobiliary tumors is still controversial but very useful for staging and prognosis.RésuméLes tumeurs hépatobiliaires malignes primitives regroupent principalement le carcinome hépatocellulaire (CHC), le cholangiocarcinome et le cancer de la vésicule biliaire. L’intérêt de la TEP pour ces tumeurs est variable selon leur localisation et leur type histologique et est encore controversé. Elle semble en revanche être d’une grande utilité dans le bilan d’extension de la maladie ainsi que pour l’évaluation pronostique.