Brain metabolic abnormalities during gait with freezing in Parkinson's disease.

INTRODUCTION: Freezing of gait (FoG) is a debilitating gait disorder in Parkinson's disease (PD). In advanced PD patients with FoG, the supraspinal locomotor network may be dysregulated (relative to similar patients without FoG) during gait. Here, we sought to characterize the metabolism of locomotor networks involved in FoG. METHODS: Twenty-two PD patients (11 with off-drug FoG and 11 without) each underwent two [(18)F]-fluorodeoxyglucose PET brain scans in the off-drug state: one at rest and another during radiotracer uptake while performing a standardized gait trajectory that incorporated the usual triggers for FoG. RESULTS: For the 11 freezers, FoG was present for 39% (± 23%) of the time during the gait trajectory. The FoG-associated abnormalities were characterized by (i) hypometabolism in frontal regions (the associative premotor, temporopolar and orbitofrontal areas, i.e. Brodmann areas 6 and 8), (ii) hypermetabolism in the paracentral lobule (Brodmann area 5), and (iii) deregulation of the basal ganglia output (the globus pallidus and the mesencephalic locomotor region). CONCLUSION: FoG during a real gait task was associated with impaired frontoparietal cortical activation, as characterized by abnormally low metabolic activity of the premotor area (involved in the indirect locomotor pathway) and abnormally high metabolic activity of the parietal area (reflecting the harmful effect of external cueing).

Surgical management of Moyamoya disease and syndrome: Current concepts and personal experience.

In this focus, we review, in the light of the recent literature, the modalities and indications of surgical cerebral revascularization for Moyamoya (MM) disease or syndrome. We also report our experience in the surgical management of adult MM. In symptomatic forms, with presence of severe disturbances of perfusion or cerebrovascular reactivity on multimodal imaging work-up, the risks of recurrent ischemic or hemorrhagic stroke is high (respectively 10-13%/yr and 2-7%/yr). The objective of treatment is to augment cerebral perfusion (in ischemic forms) or to reduce lenticulo-striate neovessel overload (in hemorrhagic forms), by initiating the development of a cortical neovascularization and/or by directly increasing cerebral blood flow. The risk of immediate postoperative death or stroke is similar between indirect and direct or combined techniques and respectively 0-0.5% and 3-6%, provided a strict perioperative anesthetic management is applied (normocapnia, normoxia and controlled hypertension). Indirect techniques (i.e. encephalo-duro-arterio-myo-periosteo-synangiosis or multiple burr-holes) are technically easy, allow wide cortical revascularization and are very efficient in children: absence of clinical recurrence in more than 95% of cases and presence of a good neovascularization in 83%. However, their effect is delayed for several months, the impact on the hemorrhagic risk is moderate and the global response is uncertain in adults. Direct (superficial temporal artery to middle cerebral artery bypass) or combined techniques improve cerebral blood flow immediately and significantly. They are associated with a higher rate of stroke-free survival at 5 years (95% vs 85%). A recent randomized study has proven that they could reduce the hemorrhagic risk by 2- to 3-fold in comparison with conservative treatment alone. However, their feasibility in children is limited by the very small size of vessels. We present also our results in the surgical management of 12 adult MM patients (mean age 41.3, sex ratio=1) operated between 2009 and 2014 (14 revascularization procedures: EDAMS 2, multiple burr-holes 1, combined revascularization procedures 11). MM types according to clinical presentation were the following: ischemic 8, hemorrhagic 2, combined 2. All patients were recently symptomatic, with recurrent ischemic/hemorrhagic events (2/3) or crescendo neurological deficit (1/3) in association with severe alterations of cerebral blood flow. Mean clinical and radiological follow-up was 22 months. Postoperative mRS at 6 months was improved or stable in 92%. None of the patients suffered recurring stroke. In conclusion, surgical treatment should be discussed quickly in symptomatic forms of MM (progressive or recurring) because of their poor outcome. Indirect techniques are favored in pediatric patients due to their simplicity and good clinical results. Direct, or preferentially combined techniques would be more effective in adult patients to prevent the recurrence of ischemic or hemorrhagic stroke.

[Power Doppler sonography and acute pyelonephritis in children: comparison with Tc-DMSA scintigraphy]. / Echographie doppler énergie et pyélonéphrite aiguë de l'enfant: comparaison avec la scintigraphie au DMSA-Tc.

UNLABELLED: Acute pyelonephritis is a common infection in children. The clinical and biological diagnosis is still sometimes difficult. For most authors, Technecium 99m dimercaptosuccinic acid scintigraphy is considered as the gold standard tool for diagnosis but it is invasive and expensive. The aim of our study was to compare the sensitivity and the specificity of B-mode sonography and power doppler to DMSA-Tc scintigraphy in acute pyelonephritis. PATIENTS AND METHODS: Forty-nine children were enrolled in this study with suspicion of pyelonephritis. All infants underwent doppler sonography and scintigraphy within 48 hours after their hospitalization. Doppler sonography criteria were increased kidney size, thickness of sinus wall, vascular defect, and various echogenicity of the kidneys (focal or diffuse hyperechogenicity or focal hypoechogenicity). RESULTS: Among 28 children with a positive scintigraphy, 15 had a positive doppler sonography (sensitivity 54%) and 13 had a negative doppler sonography. Among 21 children with a negative scintigraphy, 20 had a negative doppler sonography (specificity 95%) and one had a positive doppler sonography. CONCLUSION: In clinically suspected acute pyelonephritis, doppler sonography has a high specificity. A positive doppler sonography should avoid the use of scintigraphy.

Pulmonary embolism: prospective comparison of spiral CT with ventilation-perfusion scintigraphy.

PURPOSE: To compare prospectively the accuracy of spiral computed tomography (CT) with that of ventilation-perfusion scintigraphy for diagnosing pulmonary embolism. MATERIALS AND METHODS: Within 48 hours of presentation, 142 patients suspected of having pulmonary embolism underwent spiral CT, scintigraphy, and (when indicated) pulmonary angiography. Pulmonary angiography was attempted if interpretations of spiral CT scans and of scintigrams were discordant or indeterminate and intermediate-probability, respectively. RESULTS: In the 139 patients who completed the study, interpretations of spiral CT scans and of scintigrams were concordant in 103 patients (29 with embolism, 74 without). In 20 patients, intermediate-probability scintigrams were interpreted (six with embolism at angiography, 14 without); diagnosis with spiral CT was correct in 16. Interpretations of spiral CT scans and those of scintigrams were discordant in 12 cases; diagnosis with spiral CT was correct in 11 cases and that with scintigraphy was correct in one. Spiral CT and scintigraphic scans of four patients with embolism did not show embolism. Sensitivities, specificities, and kappa values with spiral CT and scintigraphy were 87%, 95%, and 0.85 and 65%, 94%, and 0.61, respectively. CONCLUSION: In cases of pulmonary embolism, sensitivity of spiral CT is greater than that of scintigraphy. Interobserver agreement is better with spiral CT.

Diagnosis of pulmonary embolism with spiral CT: comparison with pulmonary angiography and scintigraphy.

PURPOSE: To evaluate the accuracy of spiral computed tomography (CT) in the noninvasive diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS: A prospective study was performed in 75 patients who were evaluated with spiral CT and pulmonary angiography of each lung to detect central PE; 25 of the patients also underwent ventilation-perfusion (V-P) scanning. RESULTS: Spiral CT scans were technically suboptimal in three patients. CT and angiographic findings were negative for PE in 25 patients; one patient had false-negative CT findings. Findings from both studies were positive in 39 patients. CT findings of 188 central emboli corresponded exactly to those of angiography. Ten emboli were depicted only on CT scans, whereas seven emboli were identified only on angiograms because of inadequate depiction of the pulmonary arteries in the plane of the CT scans (n = 5) or because of misinterpretation of CT findings (n = 2). The prospective sensitivity of CT was 91%, the specificity was 78%, the positive predictive value was 100%, and the negative predictive value was 89%. Technical failures (n = 3) and inconclusive CT findings (n = 7) were the major limitations of spiral CT. Spiral CT enabled accurate classification of PE in 16 patients with indeterminate (n = 7) and low (n = 9) probability of PE on V-P scans. CT demonstrated central PE in two patients with normal V-P scans. CONCLUSION: Spiral CT can reliably depict central PE and may be introduced into the classic diagnostic algorithms.

[Intraoperative radioisotope detection: review of the acquired experience and perspectives]. / Détection radio-isotopique per-opératoire: revue de l'expérience acquise et perspectives.

Intraoperative radio-isotope detection is an old idea which has been recently revived following the development of new detectors. The authors describe two points of view concerning this technique: external detection or surface detection. Based on the experience of more than 250 cases, they review the current status of the indications for ttris technique in endocrine surgery. They discuss the prospects of this technique in the light of the development of nuclear medicine and the basic requirements of surgery: new tracers and intraoperative scintigraphy.

A miniature cesium iodide-photodiode detector for ambulatory monitoring of left ventricular function.

The physical characteristics of a portable nonimaging scintillation probe system for continuous ambulatory monitoring of the left ventricular function are described. The detector of the equilibrium radionuclide labeled blood pool is a single cesium iodide (CsI) crystal coupled to a silicium photodiode and interfaced to a microcomputer. The spatial properties of this small CsI crystal (1 x 1 x 1 cm3) were evaluated with various single-hole collimators. Linearity was studied in nonattenuating medium. Saturation began at 3000 cps, count loss was 10% at 4000 cps, maximal count rate was 24,000 cps. In attenuating medium, isocount curve of 5% of the maximal count rate was 100 mm deep and 160 mm wide. The most appropriate tested lead collimator to record the global ejection fraction of the left ventricle was a disc-shaped (thickness 5 mm, diameter 41 mm) single-hole (proximal aperture 8 mm, distal aperture 18 mm) collimator. Sensitivity was similar to the sensitivity of a sodium iodide nuclear probe. The detection performance appeared comparable to other available detector systems. Our results indicate that such a CsI-photodiode probe is a promising candidate for left ventricular function monitoring. The application to an ambulatory multicrystal detector system is presented and discussed.

Intraoperative radionuclear 125I-labeled metaiodobenzylguanidine scanning of pheochromocytomas and metastases.

We developed a technique to assess the feasibility of intraoperative radionuclear detection of pheochromocytomas and their metastases. Thirteen patients were entered into the study: five control subjects with nonchromaffin adrenal tumors, eight with pheochromocytomas, and one of these patients showing bone metastasis. Each subject received thyroid blockade and an intravenous injection of 500 microCi (37 megabecquerels) 125I-labeled metaiodobenzylguanidine (MIBG) 3 days before surgery. In the five control subjects, adrenal tumor uptake never exceeded the liver or spleen uptake. One patient with a negative preoperative MIBG scan demonstrated no intraoperative uptake. Five patients with pheochromocytoma had positive preoperative scans and in one other patient preoperative scanning was not done. In each of these six patients intraoperative count ratio of pheochromocytoma/liver from 14:2 to 250:16 and pheochromocytoma/contralateral adrenal ratio from 60:1.5 to 60:16 was demonstrated. An intraoperative scan in one of these patients detected two small metastatic tumor deposits previously overlooked by the surgeon after removing a larger mass that had been localized by a preoperative 131I-MIBG scan. A negative preoperative scan in one patient was followed by an intraoperative scan demonstrating a bone metastasis with a ratio of metastasis/normal bone of 10:0.5. Specimen studies demonstrated a significant MIBG uptake ratio of tumor/plasma ranging from 95 to 667 (average 404 +/- 242) greater than in control subjects (average 25 +/- 41); in the patient with metastasis the uptake ratio of metastasis/normal bone reached 98.4. We conclude that intraoperative 125I-MIBG scanning might detect pheochromocytoma deposits overlooked by preoperative 131I-MIBG scans.

Imaging of systemic Candida albicans infections with a radioiodinated monoclonal antibody: experimental study in the guinea pig.

Guinea pigs intravenously infected with Candida albicans were scanned to evaluate the use of radioiodinated monoclonal antibodies (MAb) to fungal antigens for detecting tissue infection sites. A total of 18 infected and 8 uninfected animals were used. MAb and F(ab')2 fragments directed against cell wall glycoproteins of C. albicans were labeled with 131I. Another MAb directed against a Schistosoma mansoni glycoprotein was labeled with 125I and used as a nonspecific control. Radiolabeled MAbs were injected at a dose of 12.5 micrograms (500 kBq) per animal. Images were acquired 24 h later. Animals were then killed and the dissected organs were separately gamma-counted. The number of C. albicans colony forming units (cfu) per gram was determined in each organ. A clear relationship was found between the anatomic distributions of C. albicans and 131I. The biodistribution of 131I radioactivity associated with anti-Candida MAb was greater in infected animals than in healthy animals and increased with the number of cfu per g in each organ. The distribution was highly specific in animals with Candida endophthalmitis, a pathognomic feature of organ involvement during hematogenous dissemination. In contrast, the distribution of 125I radioactivity associated with the nonspecific MAb was similar in healthy and infected animals. In infected animals, it was totally independent of the intensity of fungal infection.

[Peroperative isotopic detection in the treatment of osteoid osteoma in children]. / Détection isotopique per-opératoire dans le traitement de l'ostéome ostéoïde chez l'enfant.

Peroperative isotopic detection, which was rendered possible by use of the cadmium telluride semi-conductor probe developed by C. Proye et al., has permitted nidus removal, as well as promoting cure in case of osteoid osteoma, by limiting bone resection to a strict minimum. Five cases are presented, all children. The method seems to present great value, particularly in case of localisations involving the spine or the neck of the femur.