Fabrice Hubele

Dual-isotope 99mTc-MIBI/123I parathyroid scintigraphy in primary hyperparathyroidism: comparison of subtraction SPECT/CT and pinhole planar scan.

Purpose In patients with primary hyperparathyroidism, the preoperative imaging objective is to locate accurately and reliably uniglandular or multiglandular hyperfunctioning parathyroid, to guide surgery, particularly for minimally invasive method. Subtraction planar scintigraphy with dual-isotope (123I/99mTc-MIBI) is an efficient examination to specify abnormal parathyroid location, but without accurate anatomic reference. This lack should be avoided by a hybrid SPECT/CT image acquisition. Methods We compared planar scans (neck and mediastinum parallel-hole, associated with anterior neck pinhole) to neck and mediastinum SPECT/CT, all with subtraction (123I/99mTc-MIBI) method, in exact location of abnormal parathyroid in 50 patients with sporadic primary hyperparathyroidism. Surgical and histological findings were used as the standard of comparison. Results Sensitivity is equivalent for the 2 protocols (86% and 75% for SPECT/CT and planar protocol, respectively, P = 0.15), but SPECT/CT was highly specific (specificity 100% and 90% for SPECT/CT and planar protocol, respectively, P = 0.04). In patients with concomitant thyroid disease, subtraction SPECT/CT appeared to be more sensitive than planar protocol (88% and 62% for SPECT/CT and planar protocol, respectively, P = 0.04). Conclusions In preoperative assessment of primary hyperparathyroidism and to guide surgery, we propose to perform first subtraction SPECT/CT and to complete it with neck pinhole, only if tomoscintigraphy is negative.

Neural correlates of visual hallucinations in dementia with Lewy bodies.

IntroductionThe aim of this study was to investigate the association between visual hallucinations in dementia with Lewy bodies (DLB) and brain perfusion using single-photon emission computed tomography.MethodsWe retrospectively included 66 patients with DLB, 36 of whom were having visual hallucinations (DLB-hallu) and 30 of whom were not (DLB-c). We assessed visual hallucination severity on a 3-point scale of increasing severity: illusions, simple visual hallucinations and complex visual hallucinations. We performed voxel-level comparisons between the two groups and assessed correlations between perfusion and visual hallucinations severity.ResultsWe found a significant decrease in perfusion in the left anterior cingulate cortex, the left orbitofrontal cortex and the left cuneus in the DLB-hallu group compared with the DLB-c group. We also found a significant correlation between decreased bilateral anterior cingulate cortex, left orbitofrontal cortex, right parahippocampal gyrus, right inferior temporal cortex and left cuneus perfusion with the severity of hallucinations.ConclusionsVisual hallucinations seem to be associated with the impairment of anterior and posterior regions (secondary visual areas, orbitofrontal cortex and anterior cingulate cortex) involved in a top-down and bottom-up mechanism, respectively. Furthermore, involvement of the bilateral anterior cingulate cortex and right parahippocampal gyrus seems to lead to more complex hallucinations.

Nuclear medicine imaging of gastro-entero-pancreatic neuroendocrine tumors. The key role of cellular differentiation and tumor grade: from theory to clinical practice

Abstract Nuclear medicine imaging is a powerful diagnostic tool for the management of patients with gastro-entero-pancreatic neuroendocrine tumors, mainly developed considering some cellular characteristics that are specific to the neuroendocrine phenotype. Hence, overexpression of specific trans membrane receptors as well as the cellular ability to take up, accumulate, and decarboxylate amine precursors have been considered for diagnostic radiotracer development. Moreover, the glycolytic metabolism, which is not a specific energetic pathway of neuroendocrine tumors, has been proposed for radionuclide imaging of neuroendocrine tumors. The results of scintigraphic examinations reflect the pathologic features and tumor metabolic properties, allowing the in vivo characterization of the disease. In this article, the influence of both cellular differentiation and tumor grade in the scintigraphic pattern is reviewed according to the literature data. The relationship between nuclear imaging results and prognosis is also discussed. Despite the existence of a relationship between the results of scintigraphic imaging and cellular differentiation, tumor grade and patient outcome, the mechanism explaining the variability of the results needs further investigation.

Comparing respiratory gated with delayed scans in the detection of colorectal carcinoma hepatic and pulmonary metastases with 18F-FDG PET-CT.

Purpose In patients experiencing colorectal carcinoma, exhaustive analysis of indicates extent of hepatic and pulmonary surgery that prolongs survival of patients. Patients and Methods To localize metastasis, we compared 2 18F-FDG PET-CT imaging protocols, early respiratory gated scan, and delayed scan, to standard PET imaging procedure. SUVmax and lesion–to–healthy tissue ratio were measured in 60 pulmonary and 21 hepatic lesions by each of the 2 imaging protocols. Results In the liver, metastatic lesion–to–healthy tissue ratios significantly increased on delayed scans as compared with early scans (P < 0.001). Better ratios could not be obtained when using respiratory gated scans, whereas more lesions were detected on delayed scans. In the lungs, metastatic lesion– to–healthy tissue ratio increased significantly on delayed scans for largest lesions (P < 0.001). Ratios were not better when exploring smallest metastatic lesions or when using respiratory gated scans. Factors interfering with 18F-FDG PET-CT sensitivity are discussed, such as respiratory motion and high FDG physiological uptake in healthy liver parenchyma. Conclusions Our studies indicate that routine acquisitions should use delayed hepatic scans for all patients referred for evaluation, recurrence check, or monitoring of colorectal adenocarcinoma. Delayed pulmonary scans are useful for the largest metastatic lesions and should be used in addition to early scan. In our experience, respiratory gated scans seem to be less convenient because of a low sensitivity in detection, as compared with the delayed technique; in addition, this technique is currently complicated by some technical issues, although these might be overcome with new gated protocols.

Sequential FDG PET and MRI Findings in a Case of Human Herpes Virus 6 Limbic Encephalitis

A 50-year-old woman developed a human herpes virus 6 limbic encephalitis characterized by memory loss and somnolence, 3 weeks after a cord blood-derived stem cell transplantation. Sequential scalp electroencephalogram failed to detect seizure activity. Cerebrospinal fluid polymerase chain reaction assay demonstrated human herpes virus 6 deoxyribonucleic acid (positive, 3.74 log). Acute phase FDG PET imaging showed bilateral intense FDG uptake in both hippocampi and amygdalae. After antiviral treatment (gancyclovir followed by foscarnet), neurologic symptoms disappear gradually. Late phase FDG PET imaging showed a regression in FDG uptake representing hippocampal hypometabolism because of hippocampal sclerosis.

Unknown Multifocal Ileal Carcinoid Revealed by 18F-FDOPA PET/CT

Department of Biophysics and Nuclear Medicine (A.I., F.H., I.-J.N.), Hautepierre Hospital, University Hospitals of Strasbourg, 67098 Strasbourg, France; ICube (A.I., I.-J.N.), Unite Mixte de Recherche 7357, University of Strasbourg/Centre National de la Recherche Scientifique, and Federation de Medecine Translationnelle de Strasbourg, Faculty of Medicine, 67000 Strasbourg, France; and Departments of Pathology (G.A., J.-P.B.) and Digestive and General Surgery (N.C.-N., E.T., C.B.), Hautepierre Hospital, University Hospitals of Strasbourg, 67098 Strasbourg, France

Asymptomatic giant arachnoid cyst.

A 51-year-old male bricklayer without cerebral symptoms underwent whole-body FDG PET for suspicion of mediastinal sarcoidosis. PET/CT incidentally demonstrated a voluminous right frontal arachnoid cyst with normal glucose metabolism in the adjacent cortex. MRI demonstrated compression of the ipsilateral cerebral parenchyma and precentral, angulate, callosal, and superior frontal sulci. Functional bilateral finger-thumb paradigm MRI revealed right hemispheric reorganization of cortical motor activation with prominent activation between the inferior frontal gyrus and the postcentral gyrus.

FDG-PET/CT findings of atypical (bizarre/symplastic) uterine leiomyoma in a patient with abdominal leiomyosarcoma

Atypical (bizarre) leiomyoma is a benign uterine smooth-muscle tumor characterized by a) a significant number of cells with dense eosinophilic cytoplasm and enlarged, bizarre single/multiple hyperchromatic or multiple nuclei without tumor necrosis and b) poor mitotic activity. We report the case of an atypical (bizarre) leiomyoma revealed by focal fluoro-deoxyglucose (FDG) uptake during a PET-CT in a patient with relapsing abdominal and retroperitoneal leiomyosarcoma.

Head-to-head comparison between SRS, 18F-FDG and 18F-FDOPA PET/CT in a patient with recurrent SDHC-related jugular paraganglioma

About 30–35 % of head and neck (HN) paragangliomas (PGL) are familial. The vast majority of inherited forms are related to mutations in one of the succinate dehydrogenase (SDH) subunit genes [1–3]. F-FDG PET is highly sensitive in patients with SDHB mutation PGL. However, there are no data specifically concerned with SDHC [4, 5]. We illustrate the results of multimodality imaging in an SDHC-related recurrent HN-PGL. A 53-year-old woman was referred to our institution for tinnitus, hypoacusia and facial nerve paralysis. The following radiological investigations led to the diagnosis of right jugular PGL, which was surgically treated. Three years later, the patient reported conductive deafness with sporadic otorrhoea and