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Objective To investigate the 18F-FDG PET/CT features of medullary thyroid carcinoma (MTC), and to improve its diagnosis preoperatively.Methods Data of 18F-FDG PET/CT findings and clinical materials of 7 patients with MTC confirmed by pathology were retrospectively analyzed. SUVmaxEand SUVmaxDwere measured in primary tumor, and retention index(RI)was calculated.Results There were four patients with single lesion,two patients with double lesions, one patient with multiple lesions,four patients with lesions of irregular shape,four patients with lesions of unclear border, seven patients with lesions of uneven decreased density and five patients with calcifications in lesions.Uptake of 18F-FDG in primary tumor was lower in 2 patients,their SUVmaxEvalues were 2.5 and 2.1 respectively,and RI values were-20% and-14.3% respectively.The other five patients showed higher metabolism in both early and delayed imaging,and SUVmaxEwas 3.6-9.1 with an average of 5.8±2.1.RI was 7.5%-45.8% with the average of 21.3%±16.2%.There were five patients with cervical lymph node metastasis.The high metabolism was found in both early and delayed imaging of FDG.The ranges of SUVmaxEand SUVmaxDwere 3.2-8.2 and 3.3-9.8 respectively.None of 7 patients showed distant metastasis.Conclusion 18F-FDG PET/CT is helpful for identifying MTC and providing information about biological behavior and evaluating metastasis of MTC.
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Objective To evaluate the clinical value of 18F-FDG PET/CT for detecting tumor on physical examination people with unexplained elevated serum carcinoembryonic antigen (CEA). Methods A total of 100 physical examination people with unexplained elevated serum levels of CEA in our hospital from June 2010 to December 2014 were involved in the study. All the people were detected with 18F-FDG PET/CT. The pathology, clinical follow ups and conventional medical imaging results were combined to evaluate the value of 18F-FDG PET/CT in diagnosing tumor. The doubling time (DT) of CEA was calculated in the patients who were received more than twice of serum CEA detection. The relationships between serum CEA levels, CEA DT and 18F-FDG PET/CT imaging were analyzed. The receiver operating characteristic (ROC) curve was used to assess the diagnostic efficiency of serum CEA. Results Twenty-seven patients were confirmed with malignant tumor, and the rest of 73 cases were excluded. The 18F-FDG PET/CT reported one false positive and one false negative respectively. The sensitivity, specificity, accuracy, positive and negative predictive values of 18F-FDG PET/CT in diagnosing malignant tumors were 96.3%, 98.6%, 98.0%, 96.3% and 98.6% respectively. The median serum CEA levels were significantly higher in the positive 18F-FDG PET/CT patients than those in the negative patients (Z=5.796, P180 d and DT180 d and patients with DT0.05). The area under the curve (AUC) of serum CEA was 0.894, the optimal diagnostic cutoff value was 14.24μg/L. Conclusion 18F-FDG PET/CT is a useful image modality for detecting malignant tumors in patients with unexplained elevated serum CEA, especially for patients with CEA≥14.24μg/L and increase progressively.
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La opción de un injerto vascular es una medida correctiva para pacientes con enfermedad arterial periférica o aneurismas y para acceso arteriovenoso en pacientes con hemodiálisis crónica. A partir de la colocación de una prótesis de injerto vascular se puede desarrollar infección asociada en el 1-6% de los pacientes, con una alta incidencia de mortalidad del 13 al 58%. El diagnóstico de una infección asociada a injerto vascular se realiza a partir de hallazgos clínicos, microbiológicos e imagenológicos, para así definir, además de su presencia, su compromiso y extensión. El manejo ideal requiere de tratamiento quirúrgico y antibioticoterapia; sin embargo, el tratamiento quirúrgico no siempre es posible. Reportamos este caso de manejo médico exitoso de una infección de injerto vascular de aorta en la cual el 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) presentó utilidad como método diagnóstico y de seguimiento.
The option of a vascular graft is a corrective intervention for patients with peripheral artery disease, aneurisms, and to achieve arterio-venous access in patients on chronic hemodialysis. Infections from a prosthetic vascular graft occurs in 1 to 6% of patients, and this development is related to the incidence of mortality of 13 to 58%. The diagnosis of a vascular graft infection is made via the combination of clinical, microbiologic and imaging findings that allow a definition of not only the presence of infection but also its severity and spread. The ideal approach requires both surgical and antimicrobial therapy; however, the former is not always possible. We report a case of successful medical management of an aortic vascular graft infection and the usefulness of a 18F-fluorodeoxyglucose positron emission tomography/computedtomography (18F-FDG-PET/CT) scan as a tool for diagnosis and follow-up.
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Assistência ao Convalescente , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons , Enxerto Vascular , Aorta , Próteses e Implantes , Mortalidade , Diálise Renal , Transplantes , Doença Arterial Periférica , InfecçõesRESUMO
Objective To explore the significance of 18fluorodeoxyglucose positron emission tomography(18F?FDG PET/CT)in the etiological diag?nosis of postoperative intestinal obstruction in patients with gastrointestinal cancer. Methods A total of 51 patients with postoperative intestinal ob?struction undergone 18F?FDG PET/CT were enrolled for the study. The images were interpreted by visual and semi?quantitative analysis(maximum standard uptake value,SUVmax). All the cases were confirmed by pathology and clinical follow?up for more than half a year. The sensitivity,specifici?ty and accuracy of 18F?FDG PET/CT for detecting malignant intestinal obstruction were calculated. Results Of the 51 patients,35 cases were con?firmed for malignant intestinal obstruction,and 16 cases were caused by other benign diseases. 18F?FDG PET/CT imaging was positive in 36 cases, and 33 cases were diagnosed as malignant and recurrent intestinal obstruction. Three cases of PET false?positive were peritonitis adhesion and anasto?motic inflammation. Two cases of PET false negative were peritoneal micrometastasis. The SUVmax of malignant lesions was 8.86±4.82,and the SUVmax of benign lesions was 2.05±1.95. The uptake of FDG was significantly higher in malignant intestinal obstruction than in benign intestinal obstruction (t=7.15,P<0.01). The sensitivity,specificity,and accuracy of 18F?FDG PET/CT diagnosis of malignant lesion were 94.3%,81.3%,and 90.2%, respectively. Conclusion The uptake of 18F?FDG in malignant intestinal obstruction was higher than that in benign intestinal obstruction. 18F?FDG PET/CT have a good diagnostic value for the intestinal obstruction of postoperative gastrointestinal cancer.
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Objective To evaluate the accuracy, of different threshold segmentation of 18FDG PET for target volume delineation of non-small cell lung cancer(NSCLC) and the potential influence on radiotherapy treatment planning. Methods Eight NSCLC patients who had tumor with clear margin on CT scan and the amplitude of tumor movements not more than 5 mm were enrolled. PET scans were carried out at 1 h after intravenous injection of 18FDG with CT image for attenuation revisement. Gross target volume (GTV) delineated on CT image ( GTVCT ) was used as the standard. Then, GTVs were delineated on PET image with three different threshold segmentation of 42% Imax(total) (42% of maximum voxel intensity within the tumor) ,Iback + 20% Imax-back(max) (mean background intensity + 20% of normalized background-subtracted maximum voxel intensity within the tumor) and Iback -20% Imax-back(slice) (mean background intensity + 20% of normalized background-subtracted maximum voxel intensity of each slice within the tumor) ,the corresponding GTV was named as GTV42%, GTV20%max and GTV20%slice. Both the size of GTV42%, GTV20%max, GTV20%slice and GTVCT,and the coverage over GTVCT for each GTV were compared. A three dimensional margin of 1 cm were added to GTVCT, GTV42%, GTV20%max and GTV20%slice to form corresponding PTVCT, PTV42%, PTV20%max and PTV20%slic e. Three dimensional conformal radiotherapy treatment plans were designed based on PTVCT,PTV42% , PTV20%max and PTV20%slice respectively for each patient. The prescription dose of all PTVs was 66 Gy in 33 fractions in 6.6 weeks. Both the volume accepting dose less than 95% of prescription dose within PTVCT ( VPTV ) and the lung V20 were compared among the four plans based on different PTVs. Tumor control probability(TCP) as well as lung normal tissue complication probability (NTCP) were also compared. Resuits Eight patients were enrolled in this study. Median deviation of volume between GTVPET and GTVCT were -54.1% , -21.5 % and 5.3 % for GTV42% , GTV20%max and GTV20%slice, respectively. Median coverage over GTVCT of GTV42% , GTV20%max and GTV20%slice was 45.9% ,78.0% and 95.3% respectively( F = 57.50,P＜0.01). Median 7.5% of VPTV was observed for radiotherapy treatment plan based on PTV42% ,which meant that it might induce median 1% decrease of TCP comparing with that of radiotherapy treatment plan based on PTVCT. Whereas,there were only 1.3% and 0.0% of VPTV for treatment plans based on PTV20%max and PTV20%slice respectively. As far as TCP was concemed, both PTV20%max group and PTV20%slice group were superior to PTV42% group,there was no significant difference among PTV20%max group, PTV20%slice group and PTVCT group. Lung V20 and lung NTCP showed no significant difference among all groups. Conclusions The threshold segmentation of Iback + 20% Imax-back(slice) , being slice specialized, might be an optimal threshold segmentation for target volume delineation of lung caner. Independent of information of target volume provided by CT scan in advance,it is recommended to use for the target volume delineation of NSCLC with atelectasis.