Yihui Guan

18F-FP-CIT PET imaging and SPM analysis of dopamine transporters in Parkinson's disease in various Hoehn & Yahr stages.

To investigate the usefulness of 18F-FP-CIT PET for assessing the severity of Parkinson’s disease (PD) at various clinical stages, 41 patients with PD were divided into early (Hoehn&Yahr I-II, nxa0=xa023) and advanced (Hoehn&Yahr III-IV, nxa0=xa018) subgroups. 18F-FP-CIT PET was performed in these patients and 12 normal subjects. 18F-FP-CIT uptake in striatal subregions and its correlation with UPDRS were first evaluated by ROI analysis, and between-group differences were also analyzed by Statistical Parametric Mapping (SPM). Our results showed that striatal 18F-FP-CIT binding were significantly reduced to 70.9% (caudate), 46.8% (anterior putamen) and 24.0% (posterior putamen) in early PD compared with that of the control, and to 52.0%, 34.5% and 16.5% correspondingly in advanced PD, respectively. There was significant negative correlation between total motor UPDRS score of all parkinsonian patients and 18F-FP-CIT uptake in caudate nucleus (rxa0=xa0−0.53, pxa0<xa00.001), anterior putamen (rxa0=xa0−0.53, pxa0<xa00.001) and posterior putamen (rxa0=xa0−0.61, pxa0<xa00.001). SPM comparison of 18F-FP-CIT uptake between early or advanced PD and the control group showed significant decline in striatum, predominantly localized on the contralateral side and in the dorsal-posterior putamen. These results indicate that 18F-FP-CIT PET can serve as a suitable biomarker to represent the severity of PD in early and advanced stages.

Modulation of metabolic brain function by bilateral subthalamic nucleus stimulation in the treatment of Parkinson's disease.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) was proposed as an effective way to improve the symptoms of Parkinson’s disease (PD). We studied metabolic modulation in the brain by bilateral STN stimulation using FDG PET. Five PD patients (age 61.6xa0±xa03.9xa0years) at advanced stage were scanned under OFF and ON conditions of stimulation. Network analysis was used to evaluate the effect of stimulation on the expression of an abnormal Parkinson’s disease-related spatial covariance pattern (PDRP). In addition, statistical parametric mapping was used to assess the effect of this intervention on regional glucose metabolism. We found that bilateral STN DBS led to a significant reduction (Pxa0<xa00.02) in the PDRP network activity on an individual subject basis between OFF and ON conditions, parallel to significant improvement (Pxa0<xa00.002) of clinical symptoms in these patients. The treatment also decreased glucose metabolism in the right lentiform nucleus and cerebellum, and in the bilateral ventral thalamus and precuneus, but increased metabolism in the left midbrain and pons. This was consistent with the notion that clinical benefit in a PD patient was associated with the suppression of hyperactive motor circuitry following STN stimulation. These findings suggest that DBS is more likely to function by regulating the entire neural network rather than merely exciting or inhibiting certain nuclei.

Efficacy of conventional whole-body 18F-FDG PET/CT in the incidental findings of parotid masses

ObjectiveThe objective of this study was to evaluate the incidence of incidental parotid masses with conventional whole-body 18F-deoxyglucose (FDG) PET/CT and assess the ability of PET/CT to characterize these unexpected parotid lesions.MethodsFifty eight incidental findings of parotid masses with routine FDG PET/CT whole-body scan were reviewed in this retrospective analysis, which were selected from the patients without any known or suspected parotid disease in our PET center, from June 2005 to May 2009. 51 cases were operated or underwent a biopsy after a short-term PET/CT study; the remaining 7 cases had a follow-up. Parotid mass that showed both noncontrast CT (irregular shape and blurry border) and PET malignant features (high FDG uptake, SUVmaxxa0>xa03.0) was considered as positive for malignancy. Correlation of FDG PET/CT with histology or follow-up outcome was performed.ResultsFifty eight unexpected findings of parotid masses accounted for 0.3% of the total cases in 4xa0years, including 11 (19.0%) malignant tumors and 47 (81.0%) benign lesions. 13 lesions manifested single nodule with malignant CT features and intense FDG activity, of which 6 were proved to be malignant; thus, sensitivity and positive predictive values were 54.5% (6 of 11) and 46.2% (6 of 13), respectively. 45 lesions showed either single nodule with benign CT features, or a low FDG uptake (SUVmaxxa0≤xa03.0), of which 40 were true negatives; therefore, specificity and negative predictive values were 85.1% (40 of 47) and 88.9% (40 of 45), respectively. All parotid masses except 9 benign and 1 malignant showed a high FDG uptake. Compared with SUV only, combined interpretation of PET and CT results displayed a lower sensitivity (90.9–54.5%), but a higher specificity (19.1–85.1%) and a higher overall accuracy.ConclusionsWhole-body FDG-PET/CT at the time of surveying the entire body condition is helpful for detecting the asymptomatic parotid masses. Combined noncontrast CT is an essential evidence for improving the diagnostic accuracy of FDG-PET/CT for parotid masses.

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.

MRI and FDG PET/CT Findings of Primary Orbit Leiomyosarcoma.

Primary leiomyosarcoma of the orbit is extremely rare. Here we report the case of a 32-year-old woman who presented with proptosis and diplopia of the left eye. MRI examination showed a solid mass in the left orbit with invasion to adjacent tissue, and the lesion had intense FDG uptake with SUVmax of 18.7 on F-FDG PET/CT. Primary orbit leiomyosarcoma was diagnosed by surgery-pathology. F-FDG PET/CT has an advantage in excluding secondary or metastatic orbit malignancy.

Primary Uterine Cervical Lymphoma Manifesting as Menolipsis Staged and Followed Up by FDG PET/CT.

Primary uterine non-Hodgkins lymphoma of the cervix is rare. We report a 31-year-old woman presented with menolipsis for 8 weeks. Transvaginal ultrasonography and pelvic MRI detected a solid cervical mass invading the adjacent vaginal wall. The lesion showed obvious FDG uptake on PET/CT scan, and malignancy was considered. It proved to be primary diffuse large B-cell lymphoma of the cervix by biopsy. After 6-cycle R-CHOP chemotherapy, no abnormal FDG uptake was found on another FDG PET/CT scan.

Value of the Texture Feature for Solitary Pulmonary Nodules and Mass Lesions Based on PET/CT

Abstract&#12305;Objective The aim of this study was to explore the clinical value of the combination of prior knowledge of physicians and texture features for differentiation of malignant from benign solitary pulmonary nodules(SPNs) and mass lesions based on 18F-FDG PET/CT.Methods 143 patients with known solitary pulmonary nodule or mass were enrolled in the study. All the patients underwent 18F-FDG PET/CT examination.Two physicians judged the benign and malignant lesions of lung and the skewness, Angular Second Moment(ASM) and coarseness of PET/CT fusion images were measured. All patients were verified by pathological results or follow-up imagings after treatments.Results 106 patients were found to have malignant tumors and 37 patients were found with benign lesions.The sensitivity of prior knowledge&#65292;texture feature and combination of the two methods for diagnosis of pulmonary lesions were 88.7&#65285;,84.9&#65285;and 96.2%,respectively. Conclusion The result implies that combined texture feature of PET/ CT images may has potential to discriminate benign and malignant lesions and make up for deficiencies in individual parameters,and that the combination of the two methods generates better discrimination results than using one modality alone and plays a positive role for discrimination between benign and malignant lesions at present situation.