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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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<p><b>BACKGROUND</b>(18)F-fluorodeoxyglucose (FDG) is the most widely used radiotracer in tumor imaging, but its use for brain gliomas and recurrence is limited by the high (18)F-FDG uptake in normal brain tissue. (11)C-methionine (MET) has low uptake in the normal brain tissue, providing potential advantages over (18)F-FDG. The aim of the study was to investigate the diagnostic value of (11)C-MET compared to (18)F-FDG positron emission tomography and computed tomography (PET/CT) in patients with suspected primary and residual/recurrent gliomas.</p><p><b>METHODS</b>Eighty paired PET/CT scans using (11)C-MET and (18)F-FDG were performed on 44 newly diagnosed patients with suspected gliomas and 36 post-operative patients with suspected residual/recurrent tumors. PET/CT results were evaluated by visual and semiquantitative analysis. The sensitivity, specificity and accuracy for detection of gliomas and residual/recurrent tumors were calculated using visual analysis. Tumor to contralateral normal gray matter (T/G) ratio was calculated for semiquantitative analysis.</p><p><b>RESULTS</b>Final pathology of the 44 newly diagnosed patients included 26 gliomas (14 high-grade and 12 low-grade tumors) and 18 non-glioma benign lesions. Residual/recurrent gliomas were verified in 28 patients and excluded in 8/36 post-operative patients by subsequent histopathologic examination and/or clinical follow-up for more than six months. The sensitivity, specificity and accuracy of (11)C-MET PET/CT were 88.5%, 83.3% and 86.4% for gliomas and 96.4%, 87.5% and 94.4% for residual/recurrent gliomas, respectively. The sensitivity, specificity and accuracy of (18)F-FDG PET/CT were 50.0%, 88.9% and 65.9% for gliomas and 46.4%, 100.0% and 58.3% for residual/recurrent gliomas, respectively. (11)C-MET had a higher sensitivity than (18)F-FDG (83.3% vs. 33.3%, P = 0.031) in low-grade gliomas, but had no significant difference in sensitivity from (18)F-FDG for high-grade gliomas (92.9% vs. 64.3%, P = 0.219). (11)C-MET T/G uptake ratios in high-grade gliomas, low-grade gliomas and benign lesions were 1.94 ± 0.53, 1.78 ± 0.61 and 1.06 ± 0.34, respectively. (18)F-FDG T/G uptake ratios in high-grade gliomas, low-grade gliomas and benign lesions were 1.05 ± 0.37, 0.66 ± 0.14 and 0.63 ± 0.17, respectively.</p><p><b>CONCLUSIONS</b>(11)C-MET PET/CT is superior to (18)F-FDG PET/CT in detecting and delineating gliomas and residual/recurrent tumors, especially low-grade gliomas and residual/recurrent lesions present in gray matter, but its role in non-invasive grading of the tumors is limited.</p>
Subject(s)
Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , Young Adult , Fluorodeoxyglucose F18 , Glioma , Diagnostic Imaging , Methionine , Multimodal Imaging , Methods , Positron-Emission Tomography , Retrospective Studies , Tomography, X-Ray ComputedABSTRACT
Objective To explore the value of 18F-FDG PET/CT on the assessment of chemotherapy response in patients with diffuse large B-cell lymphoma (DLBCL). Methods 18F-FDG PET/CT was performed before and after 4 cycles of chemotherapy( R-CHOP or CHOP protocol) in 53 patients with DLBCL. The patients were divided into 3 groups: complete response group, partial response group and no response group. The therapeutic response was assessed by comparing post-treatment 18F-FDG PET/CT with pre-treatment PET/CT. Complete remission (CR) rate at the end of chemotherapy was calculated. χ2 test was performed with software SPSS 13.0. Results CR rates of complete response group, partially response group and no response group were 88.5% (23/26), 73.3% (11/15) and 8.3% (1/12), respectively (χ2=23.548, P=0.000). CR rates of the complete and partially response groups were significantly higher than those of no response group (χ2=22.656, P=0.000; χ2=11.407, P=0.001). Conclusion 18F-FDG PET/CT may be useful for the assessment of chemotherapy response in DLBCL.
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Objective To assess the value of 11 C-methionine (MET) PET/CT for the diagnosis of residual or recurrent glioma in comparison to 18 F-FDG PET/CT. Methods Forty-six patients suspected of residual or recurrent glioma underwent both 11 C-MET and 18 F-FDG PET/CT within 5-day interval. The glioma was considered as positive on PET/CT images based on ( 1 ) visual judgment of higher tracer uptake compared with the normal gray matter; (2) semiquantitative analysis of tumor to contralateral normal gray matter (T/G) and contralateral normal white matter (T/W) ratios. The diagnosis was confirmed by stereotsctic biopsy or radiological findings of MRI or CT and clinical follow-up ( ＞6 months). The Chi-square test and paired t test were used for statistical analysis. Results Residual or recurrent glioma was confirmed in 36 patients. The sensitivity, specificity, accuracy of 11C-MET and 18F-FDG PET/CT were 94.4% (34/36) vs 47.2% (17/36), 90.0% (9/10) vs 100% (10/10), 93.5% (43/46) va 58.7% (27/46) (x2 =19. 429, 1. 053, 15. 294, P ＜0.001, ＞0.05, ＜0.001 ), respectively. The T/G and T/W ratios of residual/recurrent giloma by 11 C-MET were significantly higher than those by 18 F-FDG (T/G ratio: 1.68 ± 0.23 vs 1.13 ±0.51, t = 5. 877, P ＜ 0. 001; T/W ratio: 2.52 ± 0.28 vs 1.42 ± 0. 57, t = 10. 470, P ＜0. 001 ). Conclusion 11 C-MET PET/CT is more sensitive and accurate than 18 F-FDG PET/CT for the detection of residual or recurrent glioma.
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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.
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<p><b>OBJECTIVE</b>To assess the value of (18)F-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography ((18)F-FDG PET-CT) in ultrasound-guided local ablation of malignant liver tumors.</p><p><b>METHODS</b>Thirteen patients with 35 local residual tumor foci following previous tumor ablation underwent (18)F-FDG PET-CT and ultrasound-guided local ablation with intratumoral alcohol injection.</p><p><b>RESULTS</b>After the second local ablation guided by (18)F-FDG PET-CT and ultrasound, radioactive defects were detected in the corresponding location in 31 of the 35 residual foci, and after the third local ablation, the other 4 foci also showed radioactive defects.</p><p><b>CONCLUSION</b>(18)F-FDG PET-CT can sensitively and accurately identify tissue necrosis and residual tumors, and serves as an excellent approach for ultrasound-guided local ablation of local residual tumors.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Ablation Techniques , Fluorodeoxyglucose F18 , Liver Neoplasms , Diagnosis , Diagnostic Imaging , General Surgery , Positron-Emission Tomography , Postoperative Complications , Retrospective Studies , Tomography, X-Ray Computed , Treatment OutcomeABSTRACT
<p><b>OBJECTIVE</b>To compare the clinical significance of PET/CT and MRI in diagnosing lymph node metastasis and N staging of nasopharyngeal carcinoma (NPC).</p><p><b>METHODS</b>116 NPC patients had undergone PET/CT and MRI before therapy. The findings of PET/CT and MRI in diagnosing lymph node metastasis and N staging were compared according to the results of follow-up.</p><p><b>RESULTS</b>A total of 614 lymph nodes in 116 patients were analyzed. 340 positive nodes and 274 negative nodes interpreted by image findings were verified during follow-up. The sensitivity, specificity and accuracy of PET/CT in diagnosing node metastasis was 93.2%, 98.2% and 95.4%, while that of MRI was 88.8%, 91.2% and 89.9%, respectively, with statistically significant difference in each between PET/CT and MRI (P < 0.05). Based on Fuzhou Staging System, 109 patients (94.0%) were correctly staged by PET/CT, and 103 patients (88.8%) by MRI, while according to UICC Staging System, 108 patients (93.1%) were correctly staged by PET/CT, and 100 patients (86.2%) by MRI.</p><p><b>CONCLUSION</b>PET/CT is superior to MRI in diagnosing lymph node metastasis and N staging of nasopharyngeal carcinoma. The false-positive and false-negative assessment based on PET-CT scan findings may be caused by: (1) inflammatory hyperplastic node; (2) node with large areas of necrosis; (3) node in diameter less than spatial resolution limitation of PET.</p>