I123-FP-CIT single-photon emission tomography in patients with long-standing mixed tremor.

BACKGROUND AND PURPOSE: Essential tremor is an abnormal movement characterized by postural and/or kinetic tremor. In some essential tremor patients, rest tremor (RT) is observed but it is not clear if this RT is a feature of essential tremor or a symptom of Parkinson's disease (PD). I123-FP-CIT single-photon emission tomography is used to distinguish essential tremor and PD. OBJECTIVES: To analyse I123-FP-CIT single-photon emission tomography in a larger series of patients with mixed tremor (i.e. action tremor associated with RT) without PD criteria. METHODS: We studied 33 consecutives patients (18 men and 15 women) with mixed tremor, clinically and by neuroimaging in all cases. RESULTS: I123-FP-CIT single-photon emission tomography was abnormal in 25 of our patients (75.7%) with mixed tremor, and we noted a reduced uptake mostly in the putamen. In our patients with abnormal imaging, RT was unilateral in 52%. In 15 of these 25 patients, putaminal reduced uptake was bilateral and symmetrical. In the other 10 patients, putaminal reduced uptake was asymmetrical or unilateral. In these 10 cases, six had a unilateral RT corresponding to (crossed) predominant reduced uptake in three cases. In our patients with normal imaging, RT was unilateral in 87.5%. CONCLUSIONS: This study shows that mixed tremor is a heterogeneous entity. The majority of patients with mixed tremor showed nigrostriatal dysfunction on I123-FP-CIT single-photon emission tomography, suggesting that mixed tremor may be a parkinsonian syndrome rather than a clinical variant of essential tremor.

Place of (18)F-FDG-PET with computed tomography in the diagnostic algorithm of patients with fever of unknown origin.

There is evidence for the interest of (18)F-fluoro-deoxyglucose positron emission tomography with computed tomography ((18)F-FDG-PET/CT) in fever of unknown origin (FUO) clinical investigation. However, little and conflicting data exist about its place in the investigation procedure. The aim of this work was to evaluate the clinical value of (18)F-FDG-PET/CT in patients with FUO and identify patients who need early (18)F-FDG-PET/CT rather than a last-resort procedure. We performed a 2-year retrospective cohort study at the Nîmes University Hospital, France. A total of 79 patients (36 men, 43 women, mean age 54.0 ± 16.2 years) with FUO underwent (18)F-FDG-PET/CT. A final diagnosis was established in 61 (77.2 %) cases. Aetiologies of FUO were determined using (18)F-FDG-PET/CT findings in 45 (73.8 % of patients with diagnosis) cases. The sensibility and specificity value were 98 % and 87 %, respectively. The presence of adenopathy, low haemoglobin and increased C-reactive protein (CRP) were predictors of high-yield (18)F-FDG-PET/CT. (18)F-FDG-PET/CT may help to detect most causes of FUO. The predictors of high-yield (18)F-FDG-PET/CT found in this study can help identify patients likely to benefit from specific and early imaging techniques.

[Camptocormia disclosing Parkinson's disease]. / Camptocormie révélatrice d'une maladie de Parkinson.

Camptocormia is characterised as an extreme bent-forward posture of the trunk that disappears in the recumbent position. On X-ray, trunk flexion appears without vertebral rotation as in scoliosis. The condition is a well-known complication of Parkinson's disease (PD) at the late stage. The authors present the case of a 77-year-old woman affected by severe camptocormia, which appeared and worsened in less than 6 months and hindered gait. Despite no signs of PD, neuro-imaging (DAT-Scan) showed an L-Dopa transducer decrease in putamens. A few weeks later, bradykinesia appeared and the clinical diagnosis of PD became more obvious. L-Dopa improved bradykinesia but did not change the bent-spine posture. A 1-year follow-up showed no other signs of PD other than bradykinesia, but the camptocormia was unchanged.

[About two big buttocks: an erysipelas with lymphoedema after pelvis surgery]. / A propos de deux grosses fesses: un érysipèle sur lymphoedème après chirurgie du pelvis.

We report the case of a 58-year-old man with erysipelas of both buttocks secondary to lymphoedema after pelvis surgery for prostatic cancer and multiple vascular interventions for iliofemoral thrombosis. The diagnosis was based on clinical examination and lymphoscintigraphy. This location of lymphoedema, limited to the buttocks, is uncommon; lower limbs are usually affected. This location needs a specific curative and preventive treatment, including antibiotic therapy, lymphatic drainage and contention to abate the condition and prevent a relapse.

A comparative study of Powell's and Downhill Simplex algorithms for a fast multimodal surface matching in brain imaging.

Multimodal images registration can be very helpful for diagnostic applications. However, even if a lot of registration algorithms exist, only a few really work in clinical routines. We developed a method based on surface matching and compared two minimization algorithms: Powell's and Downhill Simplex. We studied the influence of some factors (chamfer map computation, number and order of parameters to determine, minimization criteria) on the final accuracy of the algorithm. Using this comparison, we improved some processing steps to allow a clinical use, and selected the simplex algorithm which presented the best results.

²°¹Tl⁺-labelled Prussian blue nanoparticles as contrast agents for SPECT scintigraphy.

Prussian blue (PB) and its analogues on the nanometric scale are exciting nano-objects that combine the advantages of molecular-based materials and nanochemistry. Herein, we demonstrate that ultra-small PB nanoparticles of 2-3 nm can be easily labelled with radioactive (201)Tl(+) to obtain new nanoprobes as radiotracers for 201-thallium-based imaging.

Image resolution and magnification using a cone beam densitometer: optimizing data acquisition for hip morphometric analysis.

Bone mineral density (BMD) is a primary determinant of hip fracture risk. However, other factors, notably the femoral geometry, can influence hip fracture risk. The purpose of this study was to evaluate the potential of a new cone beam densitometer, the DMS Lexxos, in order to visualise femoral morphometry. Resolution, magnification and distortion were assessed in vitro using a line pair test pattern and a matrix test object. Results were given in comparison with currently available systems: the Hologic Discovery A and the Lunar Prodigy densitometers. The DMS Lexxos image resolution was the same in the longitudinal and transversal directions evaluated between 1.4 and 0.5 line pairs/mm (lps/mm) for an attenuation varying from 25 to 325 mm of Perplex. The longitudinal resolution was evaluated between 0.9 and 0.5 lps/mm with the Hologic Discovery densitometer, and inferior to 0.5 with the Lunar Prodigy; as for transversal resolution, it varied from 0.63 to 0.5 lps/mm and from 0.6 to inferior 0.5 lps/mm, respectively. The image was isotropic without magnification with the GE-Lunar Prodigy, whereas there was only a transversal magnification with the Hologic Discovery device. The magnification was about 1.17% cm(-1 )in the two directions, while increasing the distance of the phantom above the examination table with the Lexxos. This magnification was isotropic without distortion. The magnification could be evaluated from two images taken before and after translation of the C-arm, and a magnification correction could be applied. This method was applied to a phantom and to a human cadaver femoral bone.

Total dose incurred by patients and staff from BMD measurement using a new 2D digital bone densitometer.

Dual energy X-ray absorptiometry (DXA) is a widely used and precise technique for non-invasive assessment of bone mineral density. The DXA systems have evolved from pencil X-ray beam (single detector) to fan beam (linear array detector) and recently cone beam densitometers (bi-dimensional detector), allowing for an examination to occur without any scanning and with a short acquisition time. The purpose of this study was to evaluate patient and staff dose from a new cone beam densitometer, the DMS Lexxos. Measurements were performed on a DMS Lexxos bone densitometer prototype. An anthropomorphic phantom and thermoluminescent dosimeters were used to evaluate the effective dose. Ionization chambers and electronic personal dosimeters were used to evaluate the staff dose. The effective dose is 8.4 micro Sv for an anteroposterior spine examination and 4.8 micro Sv for a femoral neck in standard mode. The averaged scattered dose rate (ambient dose equivalent) at 1 m from the beam is evaluated at 226 micro Sv/h. Assuming six patients per hour with two views per patient, the time averaged dose rate is evaluated at 2.9 micro Sv/h. By the personal dosimeter, the staff dose (Hp 10) at 1 m from the beam is evaluated at 0.23 micro Sv per examination. For one examination, patient and staff dose from this new technology remains low: in the same range as the fan-beam densitometer.

Routine measurements of left and right ventricular output by gated blood pool emission tomography in comparison with thermodilution measurements: a preliminary study.

The aim of this preliminary study was to evaluate the accuracy of left and right ventricular output computed from a semi-automatic processing of tomographic radionuclide ventriculography data (TRVG) in comparison with the conventional thermodilution method. Twenty patients with various heart diseases were prospectively included in the study. Thermodilution and TRVG acquisitions were carried out on the same day for all patients. Analysis of gated blood pool slices was performed using a watershed-based segmentation algorithm. Right and left ventricular output measured by TRVG correlated well with the measurements obtained with thermodilution (r = 0.94 and 0.91 with SEE = 0.38 and 0.46 l/min, respectively, P < 0.001). The limits of agreement for TRVG and thermodilution measurements were -0.78-1.20 l/min for the left ventricle and -0.34-1.16 l/min for the right ventricle. No significant difference was found between the results of TRVG and thermodilution with respect to left ventricular output (P = 0.09). A small but significant difference was found between right ventricular output measured by TRVG and both left ventricular output measured by TRVG (mean difference = 0.17 l/min, P = 0.04) and thermodilution-derived cardiac output (mean difference = 0.41 l/min, P = 0.0001). It is concluded that the watershed-based semi-automatic segmentation of TRVG slices provides non-invasive measurements of right and left ventricular output and stroke volumes at equilibrium, in routine clinical settings. Further studies are necessary to check whether the accuracy of these measurements is good enough to permit correct assessment of intracardiac shunts.