[en] Objective: To study the clinical value of ¹¹C-methionine (MET) PET/CT imaging in brain glioma. Methods: 27 cases were studied including 2 glioma, 23 operated glioma and 2 healthy volunteers. ¹¹C-MET PET/CT was performed in all cases but ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in only 17 cases. Follow-up period was within 3-17 months. Results: ¹¹C-MET was negative in 4 cases and ¹⁸F-FDG negative in 3 cases in group without remnant or recurrent tumor after operation. In 2 cases of initial glioma and 19 cases with remnant or recurrent tumor group, ¹¹C-MET imaging was positive in 20 cases, tumor/gray matter ratio and tumor/white matter ratio were 2.02 ± 0.96, 3.01 ± 1.79, respectively, among them 14 cases also with ¹⁸F-FDG imaging showed positive in 12 cases. Lesions showed by ¹¹C-MET were far more clear than that of ¹⁸F-FDG. Also tumor/gray matter ratio and the tumor/white matter ratio of ¹¹C-MET imaging were significantly higher than ¹⁸F-FDG (2.15 ± 1.16 vs 0.97 ± 0.43, P<0.01; 3.31 ± 2.16 vs 1.90 ± 0.67, P<0.05 ). Conclusion: ¹¹C-MET PET/CT is superior to ¹⁸F-FDG PET/CT in the diagnosis and localization of brain glioma. (authors)

[en] Objective: To assess the clinical value of 18-fluorodeoxy glucose (¹⁸F-FDG) positron emission tomography-computer tomography (PET-CT) in preoperative evaluation of hepatocellular carcinoma patients awaiting liver transplantation and in early discovery of the recurrent focus in patients after liver transplantation. Methods: This was a retrospective study of 21 patients (34 times) with hepatocellular carcinoma who underwent ¹⁸F-FDG PET-CT. The clinical materials of preoperation and postoperation were analyzed with ¹⁸F-FDG PET-CT images. A total of 12 ¹⁸F-FDG PET-CT examinations in 10 patients were done preoperatively. Among them, the purpose of 8 ¹⁸F-FDG PET-CT examinations in 8 patients was preoperative evaluation, and the purpose of 4 ¹⁸F-FDG PET-CT examinations in 2 patients was to define the deactivation and metastasis of hepatoma in the whole body after adjuvant therapy. 22 ¹⁸F-FDG PET-CT examinations in 11 postoperative patients was performed to determine the recurrence and metastasis. The average interval between postoperative PET-CT examination and operations was 8.68 months. Results: (1) PET examinations in 2 of the 8 patients for preoperative evaluations showed no evidence of recurrence and/or metastasis, so they accepted the liver transplantations as scheduled; while ¹⁸F-FDG PET-CT examinations in 6 of the 8 patients discovered distinct extents of metastasis, 2 of them accepted the liver transplantations because of the metastasis were situated inside the operating field, but 4 of them gave up the operation because of the different extents of distant metastasis and were shifted to interventional therapy and other treatments. (2) 22 ¹⁸F-FDG PET-CT examinations in 11 patients were studied after the liver transp lactations. Among them, 2 patients were discovered no focus of metastasis, 1 patient was detected to have mycotic brain abscess, and 4 patients showed recurrence in the grafted liver. In addition, bolts of malignancy in the hepatic veins of double lobes and in the inferior vena cava, lungmetastasis, metastasis in lymph nodes, osseous metastasis, spleen metastasis, parietal pleura metastasis, and metastasis of intervertebral foramen at thoracic vertebra were revealed. Conclusion: PET-CT proved to have significant accuracy in assessing tumor-node-metastasis system staging. Two significant advantages of ¹⁸F-FDG PET-CT were the general scan of whole body and hypersensitive manifestation to carcinoma, and these diagnostic advantages result in the change of tumor staging and therapic planning in a substantial number of patients. (authors)

[en] Objective: To study the imaging manifestation of PET/CT in nasopharyngeal carcinoma (NPC) and with lymph node metastasis. Methods: 101 patients performed PET/CT were studied including 51 cases of initial diagnosis of NPC, 36 cases of treated NPC and 14 cases of nasopharyngitis. The patients with nasopharyngitis and treated NPC were followed up for more than 6 months, as lymph node metastasis 6-14 months. Results: 1) In 51 cases of initial NPC and 14 cases of nasopharyngitis, there was obvious difference among them in PET and CT manifestation. In NPC patients when nodular or massive hypermetabolism area in nasopharynx was detected in PET, the soft tissue mass or thickening was also detected in same region in CT, the diagnostic sensitivity and the specificity of PET/CT in NPC were 96.0% and 85.7%. PET/CT was superior to PET and CT in localization of tumor site, delineation of tumor border and demonstration if its invasion to surrounding tissues. 2) If the nodular or massive hypermetabolism area in nasopharynx in PET and soft tissue mass or thickening in same region in CT was considered as the remnant or relapse NPC, then the diagnostic sensitivity, specificity and false positive of PET/CT and CT was 84.6%, 91.3%, 8.6% and 92.3%, 56.5%, 43.4%, respectively. 3) Among 87 cases of NPC, lymph node accretion in neck were proved in 61 cases. The sensitivity of PET/CT and MRI were 91.8%, 88.8% (P>0.05) and the specificity were 82.2%, 51.1% (P<0.05), respectively. Conclusion: PET/CT imaging is superior to PET and CT alone in the diagnosis of NPC and also for detection of lymph node metastasis and relapse. (authors)

[en] Objective: To investigate the Furosemide intervention to promote the clearance of urinary radioactivity so as to increase the sensitivity of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT imaging for the tumor of the urogenital system. Methods: PET/CT imaging was performed in 28 patients with tumor of urogenital system. Furosemide was administrated orally or by intravenous injection 30-60 min after initial PET/CT imaging. Then drunk excess water and asked more micturation, and second regional PET/CT imaging was performed after holding urination. Compared consecutive PET/CT images, took the diuretic radioactivity level of liver and soft tissue as standard, the clearance of renal and bladder classified as good, moderate and poor. Results: The good clearance was obtained in 85.7% of patients. the tumors, which could not be detected clearly by PET/CT before the administration of Furosemide, were detected clearly after clearance in 8 cases of primary tumor and 8 cases of relapsed cancer. the use of Furosemide was not useful in 2 cases of renal clear cell carcinoma and 1 case of renal hamartoma due to absence of uptake of ¹⁸F-FDG in the lesions. PET/CT were negative in 9 cases with out relapse before and after clearance. Detection sensitivity of PET/CT were negative in 9 cases with out relapse before and after clearance. Detection sensitivity of PET/CT was 88% and was approximate to CT (83%, χ²=0.232, P>0.05), but 38.8% patients upstaged by PET/CT. Conclusions: The effect of Furosemide to promote the clearance of urinary radioactivity is quite good. It can eliminate the influence of high level of urinary radioactivity and increase the sensitivity of PET/CT imaging for detection tumor of the urogenital system. Also, PET/CT may be more useful for the staging of urogenital system tumor. (authors)

[en] A case of hepatic epithelioid hemangioendothelioma with ¹⁸F-FDG PET/CT whole-body imaging was reported. The characteristics of the disease were analyzed from clinical symptoms, laboratory and pathological examination, and imaging, and were understood through literature review. The disease has an extremely low incidence and the clinical manifestations are lack of specificity. It is not easy to be found in the early stage. It is difficult to be distinguished from common liver tumors, and easy to be misdiagnosed. The prognosis of the disease is poor. It is recognized at present that the most effective treatment is liver transplantation or radical resection. (authors)

[en] Objective: To explore the clinical value of PET/CT imaging on the diagnosis of malignancy and metastasis. Methods: 65 patients with malignancy were studied. The primary lesions were all proved by pathology and the metastatic lesions were diagnosed by the pathology combined with other imaging modalities. PET/CT fusion images, PET images and CT images of the same patient were analyzed frame by frame. Results: In 59 cases of initial diagnosis, 264 malignant lesions were detected. Among 264 lesions, 128 lesions (48.4%) were detected and displayed definitely by both PET and the plain scan of CT; 111 (42.0%) lesions were detected definitely by PET but doubtful in the plain scan of CT; while 11 patients were negative by PET but definitely by the plain scan of CT. Hence, the sensitivity of PET/CT was more higher than PET and the plain scan of CT alone. In 6 cases after therapy, PET/CT could identify necrosis and residual tumor easily and clearly whereas the plain scan of CT could not. Conclusion: PET/CT can increase the accuracy of the diagnosis and staging for malignancy. (authors)

[en] Objective: To evaluate the clinical value of PET/CT on the diagnosis and staging of lung cancer. Methods: 46 lung cancer patients including 35 pre-treatment and 11 post-treatment cases. PET/CT fusion images, PET images and CT images of the same patient were analyzed frame by frame. Results: 1) The sensitivity of PET/CT in 35 pre-treated cases reached 100%. Except one case of alveolar carcinoma showed a diffuse uptake in both lungs, the other patients displayed as hypermetabolic nodular or mass lesions with the size around 0.8-9.4 cm and the standardized uptake value (SUV) 4.6 ± 1.94. The position of hypermetabolic lesion of PET finding were all concordant to CT. PET/CT was superior to PET and CT in final diagnosis, delineating the border, detecting tumor invasion and in differentiating lung cancer from atelectasis, obstructive pneumonitis and pleural effusion. Among 11 post-treated cases, no malignancy was seen in 9 cases and in two cases with metastases in both lungs, the lesions were detected definitely by PET/CT. 2)For the staging, PET/CT was also superior to PET and CT alone with the sensitivity of 95.2%(PET/CT), 90.4%(PET), 73.8%(CT) respectively. PET and CT were complemental each other in the detection of the lesions. Obviously, PET was superior to CT in detection of small lymph node metastases, pleura, bone and adrenal metastases. CT was better than PET in detection of small lung metastases. Conclusions: PET/CT is superior to PET and CT alone in the diagnosis and staging of lung cancer. PET and CT can complement each other. (authors)

[en] Objective: To analyze the causes for diffuse bone marrow uptake of ¹⁸F-FDG on PET/CT scans. Methods: Sixty-six patients with diffuse bone marrow uptake on whole-body FDG-PET/CT imaging were enrolled for this study. Seventy-nine healthy subjects (with no history of tumor or recent fever) were selected as normal control. The SUV_max and SUV_mean were measured in bone marrow and mediastinum in both groups. The maximum (bone marrow SUV_max/ mediastinum SUV_max) and mean value ratios (bone marrow SUV_mean/ mediastinum SUV_mean) were calculated. Statistical analysis was performed by one-factor variance analysis. Results: With diffuse bone marrow uptake pattern of ¹⁸F-FDG, 27 were caused by injection of hematopoietic growth factor, 21 by hematopathy and 18 due to fever. SUV_mean of those three causes were 3.076±1.955, 3.633±2.405 and 2.546±0.791 respectively, each was significantly different from that of the control group (1.026±0.190; F=34.465, P<0.001). Conclusion: Diffuse bone marrow uptake on FDG-PET/CT are caused by both benign and malignant reasons. (authors)

[en] Objective: To retrospectively review the PET/CT imaging features of sarcoidosis and improve the diagnostic accuracy of this benign disease. Methods: The PET/CT imaging characteristics and clinical data, including lesion size, distribution, standardized uptake value (SUV) and the ratio of misdiagnosis, of 11 sarcoidosis patients (5 confirmed pathologically and 6 clinically) were retrospectively analyzed. Results: (1) Eleven patients had lymph node involvement:mediastinum and hilar lymphadenopathy in 11/11, supraclavicular fossa lymphadenopathy in 8/11, retroperitoneal lymphadenopathy in 8/11, pelvic cavity lymphadenopathy in 3/11. (2) Extra thoracic lesions were found in 7/11 with 4 lung involvement, 2 liver involvement, 1 parotid gland and temporalis involvement and 1 bilateral iliac and sacral bone involvement. (3) The size of the lesions ranged from 1.0 to 4.6 cm and the CT density ranged from 30 to 40 HU. The lesions in the lung are hypodense and in the liver are slightly hypo-or iso-dense. ¹⁸F-fluorodeoxyglucose (FDG) uptake of all lesions was definitely increased in 6 cases; ¹⁸F-FDG uptake of some lesions was moderately or definitely increased in 2 cases, and slightly increased uptake in 3 cases. (4) The PET/CT diagnosis was consistent with the final diagnosis in 6/11. The 5 cases of misdiagnosis were malignant lymphoma (4/11) and lung cancer (1/11). Conclusions: Differentiation between sarcoidosis and lymphoma in patients presenting with hilar lymphadenopathy can be difficult.Whole-body PET/CT may be helpful in the differentiation of the two diseases. (authors)

[en] Objective: Simulating injury mechanism in human peripheral nerve, acute sciatic nerve crush injuries model was produced in rabbits to investigate the relationship between the manifestations of MRI and pathology in order to provide the information for clinical therapy and operative plan. Methods: Thirty-two adult rabbits were randomly divided into two groups: group A (n=16) and B (n=16). In group A, the left sciatic nerves were crushed with a stress of 3.61 kg; In group B, with a stress of 10.50 kg. 4 time intervals in each group were observed in 1, 2, 4, and 8 weeks, respectively, and each time interval contained 4 rabbits. Left sciatic nerves were served as injured sides, right sciatic nerves were regarded as control sides. MRI was performed at different time interval after crush injury. Then the nerves were examined pathologically. Results: There were no obvious changes on T₁WI in injured sides, but the injured distal segment of sciatic nerve thickened and twisted, showing high signal intensity on 3D T₂WI, T₂WI/SPIR, B-FFE, and T₂WI/STIR. MRI could show abnormality of 30 sciatic nerves, the correct diagnostic rate was 93.75% and false negative rate was 6.25%. The distal sciatic nerve/muscle signal intensity ratio (SIR) of the injured sides was significantly higher than that of the control sides (P<0.001). However, there was no difference in SIR between group A and group B (P>0.05). SIR in injured side increased at 1 week, reached the peak at 2 weeks, at this time, nerve axons disappeared and lots of myelin degenerated, abduction function disappeared. SIR decreased during 4-8 weeks, the myelin sheath breakdown and Schwann cell proliferated obviously, and abduction functions were observed. The control sciatic nerves showed no abnormality in MRI and pathology. Conclusion: MRI can make the diagnosis of crush injury of sciatic nerve, and dynamic SIR measurement of nerve injury correlates well with the pathological and functional recovery process. MRI is an effective method to monitor degeneration, regeneration, and prognosis after injuries