Effets de l’âge et du genre sur la perfusion cérébrale régionale étudiée par deux méthodes d’analyse statistique voxel-par-voxel

Fully automated analysis programs have been applied more and more to aid for the reading of regional cerebral blood flow SPECT study. They are increasingly based on the comparison of the patient study with a normal database. In this study, we evaluate the ability of Three-Dimensional Stereotactic Surface Projection (3D-SSP) to isolate effects of age and gender in a previously studied normal population. The results were also compared with those obtained using Statistical Parametric Mapping (SPM99).MethodsEighty-nine ^99mTc-ECD-SPECT studies performed in carefully screened healthy volunteers (46 females, 43 males; age 20–81 years) were analysed using 3D-SSP. A multivariate analysis based on the general linear model was performed with regions as intrasubject factor, gender as intersubject factor and age as covariate.ResultsBoth age and gender had a significant interaction effect with regional tracer uptake. An age-related decline (p < 0.001) was found in the anterior cingulate gyrus, left frontal association cortex and left insula. Bilateral occipital association and left primary visual cortical uptake showed a significant relative increase with age (p < 0.001). Concerning the gender effect, women showed higher uptake (p < 0.01) in the parietal and right sensorimotor cortices. An age by gender interaction (p < 0.01) was only found in the left medial frontal cortex. The results were consistent with those obtained with SPM99.Conclusion3D-SSP analysis of normal rCBF variability is consistent with the literature and other automated voxel-based techniques, which highlight the effects of both age and gender.     

Intérêt de la tomoscintigraphie cardiaque à la 123I-mIBG couplée à la perfusion myocardique dans le diagnostic de l’atrophie multisystématisée

ObjectiveThe aim of this prospective study is to assess the pertinence of using ¹²³I-mIBG myocardial tomoscintigraphy coupled with perfusion scintigraphy as a diagnostic tool, to discriminate between multiple system atrophy (MSA) and idiopathic Parkinson's disease (PD) at first guided by clinical data and L-DOPA tests.Material and methodsForty patients, aged from 43 to 78 years (median 62 years) with Parkinson's syndrome were studied. Nineteen had a diagnosis of PD (criteria of brain bank) and 21 AMS (Gibbs criteria). All were given test to acute L-DOPA. Chest-centered planar imaging (128 × 128 matrix, 5 minutes of duration) is performed at 1 hour and 4 hours after injection of 220 MBq of ¹²³I-mIBG, in addition a non-synchronised tomoscintigraphy (64 × 64 matrix, 32 images of 50 seconds , zoom 1.45) was performed after the 4th hour and 15 minutes after injection of 200 to 400 MBq of ^99mTc-tetrofosmin. Besides neurological data, the parameters retained for comparison purposes with ¹²³I-mIBG cardiac tomoscintigraphy were patients’ age, duration of disease and L-DOPA test results. Two regions of interest (ROI) identical in size and in shape are used for ¹²³I-mIBG uptake quantifications (H/M and washout [Wo]). The first one was placed in projection of mediastinum (M) and the other one in projection of heart (H).ResultsWe found an overall decreased uptake of the myocardial ¹²³I-mIBG without perfusion abnormality in 15 of 19 patients with PD and 11 among them were L-DOPA sensitive (L-DOPA test greater than 30%). Normal tracer uptake with ¹²³I-mIBG associated with an almost quite normal perfusion was seen in 15 of 21 patients with MSA and they were little or not L-DOPA sensitive (L-DOPA test less than 30%). Therefore, 10 discordant cases (25%) between cardiac scintigraphy and clinical evolution of disease with also discordant L-DOPA tests were observed. In the PD group, quantification of data enhanced the diagnostic decision with low heart to mediastinum ratio (H/M) (1.32 ± 0.15 at the early stage and 1.25 ± 0.13 at the later stage). In the MSA group, the uptake of ¹²³I-mIBG (1.66 ± 0.43 at the early stage and 1.72 ± 0.42 at the later stage) was comparable to literature data, however, with significant inter-individual variations. The association of data of scintigraphy with L-DOPA test allows to improve sensitivity in 84% and specificity in 90.5%.ConclusionOur prospective study of 40 cases shows the relevance of cardiac sympathetic postganglionic imaging with ¹²³I-mIBG coupled with myocardial perfusion scintigraphy to discriminate between MSA and PD with a higher sensitivity (71.4%) compared to the test with L-DOPA but a lower specificity (78.9%) than the L-DOPA. The difficulty of diagnosis is firstly linked to damage occurring to both the pre- and postganglionic sympathetic systems in patients with MSA and secondly to the integrity of the sympathetic nerve endings in patients with PD. However, the association of data of scintigraphy with L-DOPA test show a significant improvement of sensibility (84%).     

Scintigraphie cérébrale de perfusion et troubles cognitifs d’origine vasculaire

The vascular cognitive impairment (VCI) is a heterogeneous group of various etiologies, which share a presumed vascular cause. Although the age is the most important risk factor, the cardiovascular risk factors are also involved. A relatively high proportion of these cognitive disorders could be prevented or delayed. Only the treatment of arterial hypertension is recognized as a factor in preventing vascular dementia. MRI is the examination of choice for the investigation of cerebral vascular pathology. However, this morphological imaging is insufficient and does not provide useful functional information. Perfusion brain SPECT is not widely used in the exploration of VCI. Strategies for screening VCI are not standardized and long-term studies are needed to establish the better prevention of cognitive vascular disorders. This article aims to summarize the possible benefit of cerebral perfusion SPECT in the exploration of VCI.     

Intérêt de la scintigraphie pulmonaire de perfusion dans les dilatations des bronches de l’enfant

IntroductionBronchiectasis is a chronic disease of the lungs by repeated respiratory infection. An early and adequate diagnosis and management reduce the morbidity and mortality of this disease. The aim of this study is to emphasize the importance of the combination of Computer Tomography (CT) and lung perfusion scan (SPP) in the diagnosis and therapeutic approach.Materials and methodsForty-three children were referred in the nuclear medicine department with a clinical diagnosis of bronchiectasis; they underwent a CT and a SPP.Results and conclusionBy analyzing the results of the SPP and CT separately, we conclude that there is no significant difference between the two investigations. The combination of the two explorations provides a gain in most surgical therapeutic orientation.     

Intérêt de la TEP dans le bilan d’extension et l’évaluation de la maladie résiduelle des séminomes testiculaires : étude rétrospective

AimsTo evaluate the value of PET/CT comparatively to CT in staging and restaging after chemotherapy of testicular seminoma, to assess quantitative methods and prognostic value of PET in post-chemotherapy residual masses.MethodsThirty-two patients and a maximum of 65 targeted lesions visualized on PET-CT and CT performed for staging and therapeutic response assessment were analysed and compared. Each lesion was quantified according to miscellaneous SUV normalized methods. Optimal threshold of SUV for prediction of residual disease was obtained (ROC method). The prognostic value of PET/CT at the completion of treatment was determined with progression free survival study (Kaplan-Meier method).ResultsPET/CT exhibited higher accuracy than CT in the initial staging and assessment of therapeutic response, respectively 98% versus 83.3% and 95.1% versus 75.6%. Quantification, whichever method, was not more efficient than visual reading for prediction of residual disease. Progression-free survival was higher with negative than with positive PET/CT (P = 0.0033).ConclusionOur work demonstrates that PET/CT exhibits better accuracy than CT in both staging and restaging at the end of treatment. Quantification methods do not improve accuracy of PET/CT for prediction of viable residual disease. The prognostic value of PET/CT appears very promising and needs to be confirmed by large prospective studies. PET/CT appears to be a relevant method of prognostic stratification of the risk of relapse in seminoma.     

Intérêt de l’imagerie hybride TEMP-TDM dans l’exploration des infections

Single-Photon Emission Computed Tomography-Computerized Tomography (SPECT-CT) is a new hybrid technique which offers new diagnostical capabilities in daily nuclear medicine practice. This technique not only allows to acquire fusioned anatomic and functional images in the same time, but also, it increases sensitivity and accuracy of SPECT thanks to attenuation and scattering corrections got from transmission data. Until now, SPECT-CT data have been mainly obtained in oncology and cardiology, but now, many authors use it in many scan studies and particularly for infectious diseases. In inflammatory bowel diseases, SPECT-CT seems to increase diagnostical performances and to modify management of many patients. In suspected vascular sepsis, SPECT-CT could increase sensitivity of white blood cell scintigraphy but also its specificity thanks to spatial resolution of CT. In osteoarticular sepsis, SPECT-CT has the advantage to distinguish osteomyelitis from soft tissue infection and to guide biopsies. Nevertheless, in the light of PET-CT works, SPECT-CT development will probably modify nuclear medicine practice and many studies have to be conducted to highlight consensual procedure guidelines.     

Intérêt de l’analyse de la morphologie fine et de la qualité nucléaire des spermatozoïdes dans le cadre des techniques d’AMP

Routine semen examination does not identify minor malformations of the sperm nucleus and chromatin architectural defects, which may be associated with ART outcome and cannot be detected by the embryologist even at 1000x magnification. Recent publications have demonstrated the advantages, compared to routine analysis, of a new method of real-time detailed morphological evaluation of motile spermatozoa: motile sperm organellar morphology examination (MSOME). MSOME is performed with an inverted light microscope equipped with high-power differential interference contrast optics enhanced by digital imaging to achieve a magnification of 10000x. To be considered morphologically normal, a sperm nucleus must have both a normal shape and a normal chromatin content. The aim of the present study was to combine MSOME and sperm DNA fragmentation characteristics to assess reproductive outcome. The study population consisted of the male partners of 52 couples referred for conventional IVF or split cycles (half IVF-half ICSI cycles) and exhibiting normal routine sperm parameters. Spermatozoa were analysed by examining the fine nuclear morphology and DNA integrity using the sperm chromatin dispersion test (SCD test), based on the principle that the deproteinized nuclei of spermatozoa with nonfragmented DNA show extended halos of DNA dispersion that are either absent or only minimally present in sperm nuclei with fragmented DNA. Fertilization rates were significantly lower in the group showing less than 8% of normal spermatozoa according to MSOME criteria, but early embryo development was not affected. Fine sperm morphology correlated with DNA fragmentation rate. These results demonstrate that the assessment of sperm nuclear normality by MSOME analysis and SCD test improves characterization of the semen sample and should be evaluated as a tool for allocating patients to specific assisted reproduction treatments.     

Intérêt de la spectrométrie de masse de type MALDI-TOF pour l’identification des champignons filamenteux

Identification of filamentous fungi, molds and dermatophytes, is currently based on the morphological study of colonies and therefore the experience of the mycologist. These techniques are not sufficiently precise to distinguish between different species within the same section. Furthermore, identification can be delayed for several weeks due to subcultures on specific media. MALDI-TOF MS allows correct identification of filamentous fungi until the species level in more than 95% of cases in most studies. MALDI-TOF MS is a fast and precise identification technique for filamentous fungi; however most of the different databases need to be further evaluated in routine and completed to broaden the spectrum of species identified.     

Intérêt de l’interprétation collégiale de l’échographie cervicale,de la scintigraphie 99mTc-MIBI et de la TEP-TDM à la 18-Fluorocholine dans l’hyperparathyroïdie primaire : expérience du service de médecine nucléaire de l’hôpital Cochin

ObjectivesThis study aims to assess performances of preoperative conventional imaging (99mTc-MIBI scintigraphy, cervical Ultrasonography) and 18F-fluorocholine PET/CT (FCH PET/CT) exams in the detection of hyperfunctioning parathyroid gland(s) in patients operated from primary hyperparathyroidism (pHPT).MethodsBefore surgery, 51 consecutive patients with biochemically confirmed pHPT had successively cervical ultrasonography (cUS), 99mTc-MIBI scintigraphy and FCH PET/CT, all performed in the same Nuclear Medicine Department. 99mTc-MIBI scintigraphy were performed immediatly after cUS and interpreted by same operators. FCH PET/CT exam were interpreted independently by two nuclear medicine physicians. An additional interpretation session integrating the three imaging modalities read in consensus as a combined imaging set was performed.ResultsAt surgery, 69 lesions were removed: 32 parathyroid adenoma and 37 parathyroid hyperplasia. 70% of patients had single-gland disease and 30% had multiglandular disease at histopathology analysis. In the patient-based analysis, sensitivity and accuracy in the detection of single gland disease) for FCH PET/CT, cUS and for 99mTc-MIBI scintigraphy were 86% [0.71–0.94] and 86% [0.70–0.95], 69% [0.52–0.81] and 69% [0.51–0.83], 40% [0.26–0.56] and 40% [0.24–0.58], respectively. Sensitivity and accuracy of the combined imaging set for the detection of single gland disease were 94% [0.81–0.99] and 94% [0.81–0.99].ConclusionOur results suggest that cUS/99mTc-MIBI scintigraphy and FCH PET/CT interpreted during a comprehensive session could be the ideal practice to precisely localize parathyroid lesion(s) in patients with pHPT before surgery.     

Intérêt de l’utilisation de la scintigraphie osseuse dans le diagnostic et le suivi de l’ostéochondrite primitive de la hanche

Osteochondritis, or Legg-Calvé-Perthes disease (LCP), is a necrosis of the proximal femoral epiphysis. This vascular accident entails on the complex phenomenon of growth of the child's hip and can result in deformations or even a strict destruction of the proximal femoral epiphysis. The aim of this article is to show the interest of the bone scintigraphy (BS) in precocious diagnosis and follow-up of LCP disease. In this aim, we introduced a clinical case of LCP disease where BS allowed a precocious diagnosis and a strigent monitoring. Discussion of case includes a systematic review of literature.     

Intérêt de l’imagerie hybride TEMP-TDM pour la détection du ganglion sentinelle dans les cancers du sein

IntroductionSingle-Photon Emission Computed Tomography-Computed Tomography (SPECT-CT) is an hybrid technique which associates functional and morphological images. The aim of this study was to assess the role of SPECT-CT lymphoscintigraphy in sentinel node identification in patients with breast cancer.MethodsTwelve months prospective study was undertaken. Lymphoscintigraphy comprising planar and SPECT-CT acquisition was performed in 51 consecutive patients with breast cancer (mean age: 62 ± 11.3, range: 33–83 years). Planar and SPECT-CT images were interpreted separately and the two imaging techniques were compared with respect to their ability to identify sentinel node.ResultsAn add-value of SPECT-CT images was evidenced in 31% of cases: a more accurate anatomic localization in 21% of cases and identification of undeterminate sites of uptake in 10% of cases. Furthermore, SPECT-CT detected intramammary (4% of cases) and retromammary (2% of cases) sentinel nodes missed by planar imaging. SPECT-CT was more sensitive for internal mammary drainage detection (6% of cases). The added value proved higher in obese patients. Finally, functional and anatomical images fusion and three-dimensional overview provided clear and readily usable informations to the surgeon.ConclusionHybrid SPECT-CT imaging improves the preoperative localisation of sentinel nodes in patients with breast cancer, in particular in obese patients. SPECT-CT provides readily usable informations to the surgeon.     

L’apport de la neuro-imagerie dans la maladie d’Alzheimer

Today, the role of neuroimaging in the diagnosis of Alzheimer’s disease (AD) extends beyond its traditional role of excluding other conditions such as neurosurgical lesions. Modern challenges for neuroimaging techniques aim to contribute to the early diagnosis of AD. Early diagnosis includes recognition of pre-demented conditions, such as people with mild cognitive impairment (MCI) or with high risk of developing AD. In addition, early diagnosis would allow early treatment using currently available therapies or new therapies in the future. In this article, we will present the modern role of neuroimaging in AD. Structural MRI can detect and follow the time course of medial temporal lobe atrophy as a surrogate marker for the pathological process. New MRI techniques and image analysis software can detect subtle brain diffusion, perfusion or metabolic changes thus providing new tools for studying the pathological process. New ligands are also available for studies using tracers and positron emission tomography.     

Intérêt de la TEP/TDM dans le diagnostic de la carcinose péritonéale : à propos d’une observation

PET/CT is a significant examination recognized in the detection of tumors and their metastases. Through a rare case of peritoneal carcinomatosis complicating an endometrial carcinoma, the authors discuss utility of FDG-PET/CT in the diagnosis and follow-up of this disease.