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<p><b>OBJECTIVE</b>To investigate whether fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) combined with thin-section CT improves the diagnostic performance for solitary pulmonary nodules (SPNs).</p><p><b>METHODS</b>A total of 267 patients underwent examinations withF-FDG PET/CT and thin-section CT for evaluating the SPNs with undetermined nature, which was further confirmed by pathological examination or clinical follow-up. The performance of two diagnostic criteria based on findings in PET/CT alone (Criterion 1) and in PET/CT combined with thin-section CT (Criterion 2) were compared.</p><p><b>RESULTS</b>Thin-section CT provided greater diagnostic information for SPNs in 84.2% of the patients. Compared with Criterion 1, the diagnosis based on Criterion 2 significantly increased the diagnostic sensitivity (80.4% vs 91%, P<0.01) and accuracy (76.4% vs 87.2%, P<0.01) for lung cancer. The lesion size and the CT features including lobulation, air bronchogram, and feeding vessel, but not SUVmax, were all helpful for characterizing non-solid SPNs. Thin-section CT rectified diagnostic errors in 50% (20/40) of the cancerous lesions, which had been diagnosed as benign by PET due to their low metabolism. For non-solid SPNs, Criterion 2 showed a significantly higher diagnostic sensitivity than Criterion 1 (90.0% vs 40.0%, P=0.000) but their diagnostic specificity were comparable (75.2% vs 58.3%, P=0.667). For solid nodules, the use of thin-section CT resulted in no significant improvement in the diagnostic performance (P<0.05).</p><p><b>CONCLUSION</b>The combination of PET/CT and thin-section CT creates a synergistic effect for the characterization of SPNs, especially non-solid nodules.</p>
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<p><b>OBJECTIVE</b>To investigate the characteristicF-FDG PET/CT findings in patients with primary intestinal lymphoma (PIL).</p><p><b>METHODS</b>We collected the clinical andF-FDG PET/CT data of 23 patients with PIL who underwentF-FDG PET/CT in our center between January, 2005 and January, 2016. The location, morphologies and metabolic features of the lesions were analyzed in these patients.</p><p><b>RESULTS</b>In the 23 PIL patients, diffusive large B cell lymphoma (DLBCL) and enteropathy- associated T cell lymphoma (EATL) were the primary histopathological types, accounting for 47.8% and 43.4% of the total patients, respectively. The ileum, ileocecus and ascending colon were the most commonly compromised locations (57.0%). All the 42 intestinal lesions showedF-FDG-avid foci with a mean SUVmax of 15.2∓8.1 (range 3.6-33.7), and no significant difference was found in SUVmax between DLBCL and EATL groups (t=1.851, P=0.073). Diffusive regular or irregular intestinal wall thickening was the primary CT finding in PIL lesions without significant difference between the two groups (χ=0.426, P=0.514). The aneurismal sign was found in 26.2% (11/42) lesions, more commonly seen in the patients with DLBCL than in those with EATL (χ=8.101, P=0.004). PET/CT detected abdominal lymph node involvement of lymphoma was detected in 56.5% of the patients, and a small quantity of asites was seen in 30.4% of the patients.</p><p><b>CONCLUSION</b>PIL presents with characteristic imaging features inF-FDG PET/CT.F-FDG PET/CT is a sensitive imaging modality for detecting inter- and extra-intestinal lesions of PIL and displays characteristic imaging features of the disease.</p>
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Objective To investigate the value of ~(18)F-fluorodeoxyglucose (FDG) PET/CT on the detection and staging of natural killer (NK)/T cell lymphomas.Methods Thirteen new and 2 recurrent csses of NK/T cell lymphoma were inchded in this study and they all underwent wllole-body ~(18)F-FDG PET/CT scans.A lesion with intense ~(18)F-FDG uptake was taken as positive for disease involvement and semiquantitative metabolic assessment was performed with the maximum standardized uptake value(SUV_(max)).All patients were followed for more than 6 months.The t-test was used to analyze the semi-quantitative data statistics.Results (1) ~(18)F-FDG PET/CT had 100%positive detection rate for NK/T cell lymphom.Of 11 cases with disease involvement of the nasal region.PET/CT detected 10.either in the nasal cavity or in the nasopharynx,6 with extra-nasal infiltration,and 7 with regional nodal metastasis.There were 4 non-nasal cases and PET/CT detected one or multiple extra-nasal lymphoma lesions.The SUV_(max) of nasal and extra-nasal lesions was 12.42±9.25,9.54±7.12,respectively,with no significant difference(t=1.120,P＞0.05).(2)Two cases(2/15)diagnosed of this disease by PET/CT were initially referred as investigation of fever of unknown origin.For the remaining 13/15 known cases,PET/CT detected more "unsuspected" lymphoma lesions in 7 cases and affected the staging in 6 patients.The ~(18)F-FDG uptake (SUV_(max))of Ⅰ-Ⅱ stage patients was mildly lower than that of Ⅲ-Ⅳ stage patients,but no significant difference was observed (t=0.757,P＞0.05).Conclusions NK/T cell lymphoma is an intensely ~(18)F-FDG-avid tumor.~(18)F-FDG PET/CT is an effective imaging tool for detection and staging of this disease.
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Objective To explore the value of 11C-choline PET/CT in patients with hepatic spaceoccupying lesions that have an indeterminate diagnosis by 18F-fluorodeoxyglucose (FDG) PET/CT. Methods A total of 25 liver masses in 20 patients with an indeterminate diagnosis based on 18F-FDG PET/CT were enrolled. Regional 11C-choline PET/CT scan was performed in all of the patients. Lesions with intense 11C-choline uptake were considered as positive. The semiquantitative maximum standardized uptake value(SUVmax) was measured and the tumor-to-liver (T/L) radioactivity ratio was calculated. The Mann-Whitney test,Kruskal-Wallis test and crosstabs x2-test were performed by using SPSS version 11.5. Results Of the 25 lesions,21 were proven to be hepatocellular carcinomas (HCC),3 hemangiomas,and 1 parasitic granuloma. The sensitivity of 11C-choline PET/CT for the detection of HCC was 66.7% (14/21). 11C-choline PET/CT had a higher sensitivity for well differentiated HCC than moderately and poorly differentiated HCC on a patient basis (8/9 vs 2/5,respectively). There were significant differences of 11C-choline T/L ratios between the HCC positive group,HCC negative group and benign lesion group ( 1.70 ± 0.35,0.86 ± 0.15,and 0.36 ± 0.18,x2 = 19.00,P ＜0.01 ). The lesion size and alphafetoprotein (AFP) level between the HCC positive and negative groups had no significant difference respectively ( Mann Whitney U = 39.00,P ＞0.05,and U=16.00,P＞0.05,respectively). Conclusions 11C-choline is complementary to 18F-FDG PET/CT for the detection of HCC,especially for well differentiated HCC.