Imagerie hybride dans l’embolie pulmonaire aiguë : apport de la TDM couplée à la tomoscintigraphie de ventilation et de perfusion

Purpose

V/P-SPECT lung scan can be combined with computerized tomography (CT) from hybrid camera. We investigated if CT data could be use only with perfusion scans for the diagnosis of acute pulmonary embolism (PE).

Patients and methods

In a retrospective study, 75 consecutives patients, referred for suspicion of PE, underwent SPECT ventilation and perfusion scans coupled with a CT on Symbia T2. The perfusion images (P-SPECT) were classified as normal or abnormal with systematized (segmental and sub-segmental) or not systematized perfusion abnormalities. The ventilation images (V-SPECT) were considered as normal or abnormal in light of perfusion defects. The same was done for CT images. Correlations between V-SPECT and CT were studied.

Results

Hence, 28 patients had a normal P-SPECT and did not have PE. Patients (47) had an abnormal P-SPECT (among them, 16 turned out to have PE and 31 did not). There were 192 perfusion abnormalities of which 81 were segmental and 81 sub-segmental. Corresponding to these abnormalities, V-SPECT and CT were concordant in 83 % of the cases. When not-concordant, V-SPECT abnormalities with normal CT were found in 14 % of the cases and CT abnormalities with normal V-SPECT were found in 3 % of the cases. According to the EANM guidelines for PE diagnosis, sensitivity was 88 % and specificity 93 % with V/P-SPECT and 100 % and 83 % respectively with CT/P-SPECT (p = NS).

Conclusion

V/P-SPECT remains slightly more specific for the diagnosis of PE. However, this study demonstrates that CT/P-SPECT obtained with hybrid camera could be used for PE diagnosis with performances similar to V/P-SPECT. If these results would be confirmed on larger populations, this could lead to a significant reduction of scanning time which would improve patient comfort and reduce the camera load.     

Apport de l’imagerie hybride TEMP-TDM dans le suivi d’un cancer différencié de la thyroïde

In the management of patients with differentiated thyroid cancer (DTC), abnormalities detected on planar whole body scan and ¹³¹I-SPECT are difficult to interpret because of a lack of anatomical landmarks and limited specificity. Integrated ¹³¹I-SPECT-CT imaging has an additional value for characterization of equivocal tracer uptake seen on planar imaging as well as for precise localization. We illustrate through an observation the incremental diagnostic value of ¹³¹I-SPECT-CT images in the diagnosis of a cervical lymph node mimicking a physiological uptake on planar views. A 35-year-old Tunisian female was followed for papillary thyroid carcinoma, for which she underwent total thyroidectomy and iratherapy. Three years after a complete remission, the thyroglobulin (Tg) level on TSH stimulation increased. Diagnostic planar images with ¹³¹I did not disclose any obvious pathological foci. Furthermore, we noticed an increased ¹³¹I-uptake in the left sub-mandibulary area, which suggested a salivary physiological activity. SPECT-CT of the neck and chest were then performed with a Symbia T camera. Fused images demonstrate that this activity corresponds to a cervical lymph node closely adjacent to sub-mandibulary gland. Management of the patient was then changed. In selected patients with DTC, hybrid imaging should be used as a complementary to planar imaging in terms of diagnostic accuracy, because of superior focus localization and additional anatomic information derived from the CT component. Integrated SPECT-CT is then a useful tool, especially in cases of unclear diagnoses, precising anatomical localization of areas of increased ¹³¹I-uptake and distinguishing malignant lesions from normal physiological uptakes. This is particularly important in an oncologic center, as ours, where we don’t yet have a positron emission tomography (PET) camera is not yet available.     

Caméras hybrides TEMP-TDM et semi-quantification du I-FPCIT : évaluation de l’apport de la TDM

Objectives

Tomoscintigraphy of dopamine transporters with ¹²³I-FP-CIT is nowadays essential to visualise impairment of nigro-striatal system for the diagnosis of parkinsonism and for the differential diagnosis of dementia. With the development of hybrid cameras (SPECT-CT), the CT contribution in nuclear neurology needs to be assessed in diagnostic and semi-quantification performances. The main purpose of our study is to compare attenuation correction using CT to attenuation correction using the linear algorithm of Chang. SPECT-CT with parallel collimation results were also weighed against fan beam collimation and the contribution of partial volume effect correction was studied in secondary objective.

Materials and methods

We used a trilinear phantom to define spatial resolution and an anthropomorphic striatal phantom to quantify the activity in striatal cavities. We compared the impact of attenuation and scatter correction on spatial resolution and semi-quantification in striatum. We performed the partial volume effect correction on reconstructed images according to the method of Rousset.

Results

Attenuation correction by CT did not improve significantly spatial resolution compared to the algorithm of Chang. The semi-quantification of ¹²³I-FPCIT in striata was not significantly different according to the various CA, but was significantly improved with CT attenuation and scatter correction. Partial volume effect correction improved the quantification from 40 to 60% in the striatal structures, when the activity was superior in at least twice the background noise.

Conclusion

SPECT-CT hybrid cameras increase spatial resolution and improve semi-quantification of ¹²³I-FPCIT because of CT attenuation and scatter correction. Another use of CT is the possibility of calibrating anatomic segmentation of striata for partial volume effect correction. Partial volume effect correction improves quantification and is essential for early diagnosis of nigro-striatal disease.     

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.     

Synostose talo-calcanéenne et scintigraphie osseuse à l’HMDP-Tc : intérêt des images TEMP-TDM et problèmes de diagnostic différentiel

The purpose of this case report is to illustrate the scintigraphic aspect of a common foot disease, the tarsal synostosis. We report the clinical case of a 36 years old patient with a history of repeated injuries of left ankle, and experiencing residual pain. Foot radiographs and CT scan were not contributory and a MRI exam of the foot disclosed fibrous talocalcaneal bridge in favor of a syndesmosis. Bone scintigraphy with SPECT-CT images had a double interest, showing the active inflammatory process of the synostosis and delimiting the anatomical structures related to this uptake. Medical treatment with anti-inflammatory drugs has been introduced, associated to immobilization, and followed by sessions of physiotherapy.     

Arkaïm-Sintachta : expérience de la mise en valeur des steppes eurasiatiques à l’Âge du Bronze

The “Earth of fortified settlement” is one of the last big discoveries of the end of the XXth century. Situated on the oriental slopes of the mounts of Ural, fortified settlement, date the Middle Bronze Age. These strengthened structures are particular in the archaeology of steppes. They were built according to geometrical plans, Cities in oval being the most ancient, the rectangular cities being the most recent. The most remarkable are together of strengthened structures appropriate for the culture of Sintachta-Arkaïm. This city distinguishes itself from the others by the unique integrity of the works of fortification and by the graves which are connected to these last ones. Situated on a prominence, Arkaim consists of two defensive walls, maybe of a third, the rampart and the ditch. The space between the defensive walls was occupied by the houses of shape trapezoidale and directed as beams to the center of the city. The center of the city, the rectangular shape, was not built and formed a place where foyers were found. Complex entrances were at the four corner of the city. The excavations of fortified settlement and graves allowed to have an idea on the level of development of the everyday life at the time of the Middle Bronze Age in transouraliennes plains.     

Apport de la fusion d’images tomoscintigraphiques avec la tomodensitométrie X ou l’imagerie par résonance magnétique en pathologie osseuse : expérience du service de médecine nucléaire de Sfax

The aim of our study was to assess the contribution of image fusion of SPECT combined with computed tomography (SPECT-CT) or magnetic resonance imaging (SPECT-MRI) in our daily practice of bone scintigraphy. Seventeen patients underwent a SPECT image fusion, SPECT-CT or MRI in addition to conventional bone scintigraphy. These acquisitions are made separately with images stored in DICOM format. The fusion was operated after a manual coregistration of the images. Results show that in 35.29% of cases, the image fusion allowed to pinpoint the exact location of increased uptake seen on the whole body scan and/or on static images. In 35.29% of cases, the fusion has confirmed a diagnosis doubtful in planar imaging. In five patients, representing 29.41% of cases, the fusion has corrected a diagnosis. In one patient (5.88% of cases), the fusion has eliminated a false positive related to increased uptake visualized on the whole body scan. In two patients (11.11% of cases), the fusion has eliminated false negative of bone scan in one case and of MRI in the other case. Finally, in nine patients (50% of cases), the fusion has influenced the therapeutic management.     

Intérêt de la TEP/TDM dans le bilan d’extension et le suivi des lésions osseuses du myélome multiple

Multiple myeloma (MM) is a malignant hemopathy characterized by a pathologic proliferation of plasmocyts in bone marrow. Detection of bone lesion is of great importance in initial extension screening and for the follow-up because it has an impact on therapeutic strategy. Plain radiographs do not have a good sensitivity for the detection of such lesions. Magnetic resonance imaging (MRI) is an interesting tool to detect diffuse bone marrow infiltration. We propose, based on the experience of our center and through a comprehensive review of the literature, to present the potential of [¹⁸F]-FDG PET/CT for the detection and the therapeutic strategy of bone lesions in MM.     

Cancer de la prostate : utilité de la TEP-TDM à la F-fluorocholine

In oncology, positron emission computed tomography (PET/CT) has become an essential tool for initial staging, response evaluation and follow-up of cancer patients. Most of the frequent tumors (lung, breast, esophagus, and lymphomas) are highly avid for ¹⁸F-fluorodeoxyglucose (¹⁸FDG), but prostate cancer has not demonstrated significant uptake of FDG. The development of new tracers labeled with ¹⁸F such as choline analogs allowed already to obtain interesting results particularly in patients with biological relapse and inconclusive conventional imaging work-up. The impact of ¹⁸F-flurocholine PET/CT on patient management needs to be validated in large studies, but many centers use already this examination in order to guide further management, including radiotherapy planning.     

Cancer de prostate métastatique résistant à la castration : le point de vue de l’oncologue médical

Most of patient suffering from a prostate cancer will develop a castration resistance. In this common and clinically challenging situation, chemotherapy was not considered very useful until mid 2000s. Docetaxel is now recognized as a standard of care, improving overall survival and quality of life. However, new drugs are needed. Two compounds (cabazitaxel and abiraterone) are now underway to official registration and an autologous vaccin strategy (Sipuleucel) demonstrated a benefit in survival. Based on a greater knowledge of biology, many other agents are currently under development, such as new specific peripheral anti-androgens, anti-angiogenic therapies, or proteasome inhibitors. All these new drugs are promising and may provide more efficient therapies against this incurable disease in the near future.     

Le Paléolithique moyen et supérieur de la Hongrie du nord : nouvelles investigations dans la région d’Eger

The region of Eger town at the foot of the Bükk Mountains in Northeastern Hungary has particular importance for the understanding the Middle and Upper Palaeolithic periods of the Carpathian Basin. One of the key-problems is the association of carinated tools and foliate points in the lithic assemblages of the sites. New investigations at the Egerszalók-K?vágó site give fundamental data for the animated discussion on the relation between Aurignacian and Szeletian.     

Métastase rénale d’un carcinome vésiculaire de la thyroïde révélée par le balayage du corps entier à l’iode 131

Distant metastasis of differentiated thyroid carcinoma generally affect lung and/or bone tissue. Renal metastasis from thyroid carcinoma is extremely rare. We report a case of renal metastasis from a follicular thyroid carcinoma in a 55-year-old man, occuring 11 years after total thyroidectomy, fortuitously discovered on a whole body scan carried out after 131-iodine therapy for neck recurrence of disease. Salient features of our clinical case are the fortuitous mode of discovery the unilateral localization of metastases and especially the long time interval which separates its detection from that of the primitive tumour. This case report exemplifies the useful role of the whole body scan carried out after 131-iodine therapy better adapted to reveal often undetectable occult metastases with low dose, but also to ensure a regular and protracted follow-up of patients treated for differentiated thyroid carcinoma.     

Moulin Quignon : la redécouverte d’un site

The collection from Moulin Quignon is a coherent one, despite the diversity of its pieces, in the certainty of its origin, in its attachment to the researches led on the site in 1863–1864. Considered as a historic heritage, its study has nevertheless delivered significant scientific information, valid for the present, and, beyond that, to reintroduce the site of Moulin Quignon in the oldest Palaeolithic panel sites of the Somme valley.     

Radiomarquage in vitro des leucocytes au [F]-fludésoxyglucose : première expérience à l’hôpital d’instruction des armées Val-de-Grâce

^99mTc-HMPAO (technetium^99m-hexamethylpropylene amine oxime) radiolabeled-leukocytes or Indium-111 oxine labeled leukocytes scintigraphy and positron emission tomography with [¹⁸F]-fludeoxyglucose (¹⁸F-FDG) are the reference techniques for infection imaging. These methods have some limits explaining the active research for an ideal infection tracer finding. Because of its potential advantages, leukocyte labeling with ¹⁸F-FDG have been developed but is not routinely used for clinical infection imaging. We report the results of our first experience of leukocyte radiolabeling with ¹⁸F-FDG, managed on 20 healthy subjects. Labeling efficiency, cellular viability and radiolabeling stability have been assessed. Our results exhibit the influence of different parameters on labeling efficiency: presence of glucose during the labeling reaction, number of cells and volumic activity of ¹⁸F-FDG. Stability assessment indicates that 60% of initial cellular activity persist in cells after 1 hour incubation. Our results are similar to literature data and permit us to consider a clinical use of radiolabeled leukocyte with ¹⁸F-FDG. Nevertheless, a clinical use of radiolabeled cells can’t be considered before the radiolabeling induced cellular effects have been assessed.     

Contribution à la reconnaissance d’une microproduction au Paléolithique moyen : les industries de la grotte des Ramandils (Port-La Nouvelle, Aude, France)

The Ramandils Cave is a key archeological site situated on the Mediterranean coast. The importance of this site derives not only from its geographical and chronological position, but also from the density of the artefacts left by Neandertal populations who settled there on several occasions as early as isotopic stage 5. This study concerns 29,997 lithic objects from five stratigraphical units. The industries, mainly in flint, are all small sized (< 30 mm). The Ramandils Cave lithic assemblage fits within the variability of Middle Paleolithic sites, however differing by a characteristic size reduction in knapping economy, in matrix and resulting products production. How might we interpret this small size characteristic: as a purely cultural factor or as a result of circumstances? Results show that this micro-production does appear to be predetermined. The characteristics of the lithic assemblage from Ramandils Cave give them a special status in the debate regarding the definition of micro-Mousterian and in the identification of technocomplexes geared towards micro-production.     

L’industrie en calcaire du site Paléolithique d’Isernia la Pineta : un modèle interprétatif de stratégie comportementale

The studies and the researches carried out in the last years on the Palaeolithic site of Isernia La Pineta have brought to consider in new way the activities realized by the human group that lived the basin of Isernia during the Middle Pleistocene offering an important key of interpretation of the behavioural strategies of the prehistoric man. The analysis of the exploitation of the raw material has confirmed the presence on the site of two different lithotypes: flint and limestone; the lithological dichotomy is related to the functional dichotomy of the raw material that seems to have conditioned the activities of the human group in different areas of the site. The necessity to deepen the study on the limestone has derived from the evidence brought to light in the last excavation campaigns of a remarkable concentration of the flaked limestone pebbles and the flake scars in some areas of the explored archeosurfaces, particularly on the 3a and on the overlooking layers. The present study has the purpose to explain the characteristics of the limestone finds both in reference to the raw material and to its state of preservation both to the technotypological evidences and its spatial distribution with the purpose to better understand the modalities of the exploitation of the raw material. The information collected until today have permitted to obtain a precise knowledge of the environmental context and the territorial resources exploited by the human group showing an opportunistic capability to find the most advantageous behavioural solution for the necessities of subsistence.     

Le site des Vachons : étude de la partie gravettienne de la collection de l’IPH

This article firstly summarizes the process of study of an old collection, which had not been considered since the excavations at the site Les Vachons, started before 1914 and completed around 1939. The studied collection of J. Coiffard, both excavator and inventor of this site, includes four-fifths of the artefacts because, in 1940, he donated approximately one fifth to the Eyzies Museum. For his part, J. Bouyssonie who participated in the excavations for 3 years gave the major part of his own collection to the Archaeological Society of Charentes Angouleme where its condition makes it difficult to analyze. Despite these restrictions, based on statistical comparisons with counts many other sites, I came to the conclusion that the top three layers of Les Vachons are a confirmation of the Gravettian model, developed by B. Bosselin and F. Djindjian through their factor analysis. This model seems much better suited to the stratigraphy of Les Vachons, than all assumptions made by previous analysts in their attempt to bring the industries from the three layers in what remains from the Peyrony model.     

La transgression thanétienne (Paléocène supérieur) dans l’Aurès occidental (Algérie), d’après les associations de Foraminifères de la coupe d’El Kantara

In the W-Aures (Algeria), the El Kantara pass displays about 50 m of Red Marls overlying the Maastrichtian limestones with Laffitteina. The Red Marls are, in their turn, overlain by the Thanetian marly limestones of the river El Haï. The micropaleontological inventory of these Red Marls establishes the co-occurrence of subaerian (Microcodium = Paronipora), fresh-water (Charophyta) and marine microfossils (Foraminifers). The stratigraphical significance of these microfossils is discussed. The upper part of the Red Marls, yielding abundant Valvulina and scarce Glomalveolina, is of Thanetian age. The age of the lower part is less established, but the occurrence of Microcodium suggests a Thanetian age too. Located at the margin of the northern opening of the trans-Saharan epeiric sea, the El Kantara section establishes a Thanetian age for the beginning of the Paleocene transgression. Danian deposits are missing, in spite of the absence of an obvious hiatus on the field. After general emersion during the early Paleocene, the Thanetian transgression starts with the set up of lakes at the depositional area of the Red Marls. Marine influences, limited at first, become gradually prevailing, and end with the deposition of neritic marly limestones of river El Haï.     

Les faunes d’ammonites du Pliensbachien inférieur des séries dauphinoises de la Durance (Jurassique inférieur, Barrage de Serre-Ponçon, Hautes-Alpes, France)

The Liassic ammonite faunas and especially those of the Early Pliensbachian are of major importance for the understanding of the stratigraphic framework of the “Dauphiné” zone of the southern subalpine ranges (“dôme de Remollon”). Until now, only listed by the authors, these faunas are, for the first time, described and illustrated in the present paper. With about twenty species, these faunas cover the whole of the Early Pliensbachian. There are poorly diversified and of clearly Euroboreal affinities. Nearly all of the species are abundant and common in most of the NW European fossiliferous localities. Despite of a paleogeographical location fairly close to the Alpine zones (Southern Alps and Austroalpine units) with rather diversified faunas of mainly Mediterranean affinities, none Mediterranean taxa are present in the studied area. Unfortunately, the current stratigraphic and paleogeographic knowledge do not allow to ascertain if this reflects a separation due to paleoenvironmental or true paleogeographic barriers. In this latter case, the general geologic implications would be remarkable.