Zhemin Huang

Misdiagnoses of 11C-choline combined with 18F-FDG PET imaging in brain tumours.

Background and objectiveThe widely applied 18F-FDG is known for its disadvantage in brain tumour PET imaging because of its high background uptake. 11C-choline can achieve high contrast of brain tumour imaging and was expected to have higher sensitivity and specificity. We analysed the misdiagnoses in 11C-choline PET imaging in brain tumours with the aim of improving the accuracy of diagnosis with 11C-choline PET imaging. Patients and methodsWe selected 10 patients proven to have been misdiagnosed on the basis of histopathological correlation and clinical follow-up among 94 patients (110 studies) who underwent 11C-choline PET/CT for diagnosed or suspected brain tumour between 23 March 2005 and 8 February 2007. 11C-choline PET imaging were performed on a Biograph Sensation 16 PET/CT scanner (Siemens Medical Systems), 18F-FDG imaging was also performed as reference. ResultsOf all 10 misdiagnosed patients, five were false positive (one abscess, one tuberculosis, one benign gliocyte proliferation, one inflammatory granuloma and one demyelination), four were false negative (two metastases from lung cancer, one lymphoma, one grade II glioma) and one was misdiagnosed by wrong interpretation due to lack of experience. The rate of false positives was (5/110) 4.55%; the rate of false negatives was (4/110) 3.64%; the accuracy of 11C-choline alone was (93/110) 84.5%; by comparison, the accuracy of 18F-FDG alone was (78/110) 70.9%. Conclusions11C-choline imaging has a certain rate of false positivity and false negativity. With proper application, 11C-choline might have greater potential than 18F-FDG for brain tumour PET imaging.

Differences in the metabolic status of healthy adults with and without active brown adipose tissue

SummaryBackgroundPrevious studies have proven the existence of active brown adipose tissue (BAT) in adults; however, its effect on systematic metabolism remains unclear.AimThe current study was designed to investigate the differences in the metabolic profiles of healthy adults with and without active BAT using positron emission tomography–computed tomography (PET-CT) scans in the un-stimulated state.MethodsA cross-sectional analysis was performed to assess the health of adults using PET-CT whole-body scans at Huashan Hospital Medical Centre between November 2009 and May 2010. A total of 62 healthy adults with active BAT were enrolled in the BAT-positive group. For each positive subject, a same-gender individual who underwent PET-CT the same day and who had no detectable BAT was chosen as the negative control. Body composition was measured, and blood samples were collected for assays of metabolic profiles and other biomarkers.ResultsIn both the male and female groups, BAT-positive individuals were younger and had lower body mass indexes, fasting insulin, insulin resistance, and leptin, but a greater level of high-density lipoprotein cholesterol compared with the negative controls. In the male group, body fat content and levels of tumor necrosis factor-α were significantly lower in the BAT-positive than in the negative control group.ConclusionsThe healthy adults with active BAT in an un-stimulated state had favorable metabolic profiles suggesting that active BAT may be a potential target for preventing and treating obesity and other metabolic disorders.ZusammenfassungGrundlagenFrühere Studien haben die Existenz von aktivem braunem Fettgewebe (BAT) bei Erwachsenen nachgewiesen. Die Wirkung dieses Gewebes auf den systemischen Stoffwechsel bleibt allerdings unklar.ZielDie vorliegende Studie plante zu erforschen, ob ein Unterschied in den Stoffwechselprofilen gesunder Erwachsener mit beziehungsweise ohne BAT besteht, wobei PET-CT Scans im nicht stimulierten Zustand verwendet wurden.MethodikAm Huashan Hospital Medical Center wurde zwischen November 2009 und Mai 2010 eine horizontale Analyse durchgeführt, um die Gesundheit von Erwachsenen zu erfassen, wobei PET-CT Ganzkörper Scans zur Verwendung gelangten. Insgesamt wurden 62 gesunde Erwachsene mit aktivem BAT in die BAT positive Gruppe aufgenommen. Für jede positiv getestete Person wurde als negative Kontrolle eine Person gleichen Geschlechts ausgewählt, die am selben Tag eine PET-CT Untersuchung hatte und bei der kein aktives BAT nachgewiesen werden konnte. Die Körperzusammensetzung wurde gemessen und Blutproben zur Bestimmung von Stoffwechselprofilen und anderer Bio-Marker wurden abgenommen.ErgebnisseSowohl die männlichen als auch die weiblichen BAT positiven Individuen waren jünger und hatten einen geringeren BMI, ein niedrigeres Nüchtern-Insulin, niedrigere Insulinresistenz und Leptin. Nur das HDL-Cholesterin war im Vergleich zur BAT negativen Gruppe erhöht. Bei den BAT positiven Männern war der Körperfettgehalt und die Konzentration von Tumornekrosefaktor-alpha (TNF alpha) signifikant niedriger als bei den BAT negativen Kontrollen.SchlussfolgerungenDie gesunden Erwachsenen mit aktivem BAT hatten im nicht-stimulierten Zustand ein günstigeres Stoffwechselprofil. Dies legt nahe, dass das aktive BAT ein mögliches Zielorgan bei der Vorbeugung und Behandlung der Adipositas und anderer Stoffwechselerkrankungen sein könnte.

18F-FDG imaging of a rare cutaneous infection by Mycobacterium avium complex.

A 17-year-old male patient was admitted into our hospital with granulomatous eruption (primarily on the lower extremities), diarrhea, fever, and weight loss for 6 months. F-FDG PET/CT scan was performed to rule out the possibility of malignant metastasis or paraneoplastic syndromes. F-FDG PET/CT scan showed multiple bone and skin lesions with significantly intense FDG uptakes and lymph nodes with moderate FDG uptake. A biopsy of the skin lesions was performed, and the tissue was sent for a broad-range polymerase chain reaction amplification, which showed that the pathogenic organism was Mycobacterium avium complex.

Non-Hodgkinʼs Lymphoma of Supraclavicular Lymph Nodes Can Mimic Metastasis of Breast Cancer During Chemotherapy on FDG PET/CT

A 43-year-old woman who had a history of right mastectomy for breast cancer presented with fever and swelling in the right supraclavicular region during her second course of chemotherapy. An FDG PET/CT was performed to evaluate this patient, which revealed mildly increased FDG activity in the lymph node in the supraclavicular region. A metastatic lesion from the known breast cancer was considered. However, biopsy results demonstrated that the abnormal activity in the right supraclavicular region is due to T-cell lymphoma.