Analysis on the reasons for diffuse 18F-FDG uptake by bone marrow using whole-body PET/CT / 中华核医学杂志

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 SUVmax and SUVmean were measured in bone marrow and mediastinum in both groups. The maximum (bone marrow SUVmax/ mediastinum SUVmax) and mean value ratios (bone marrow SUVmean/ mediastinum SUVmean) 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. SUVmeanof 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.

Value of positron emission tomography-computed tomography in the diagnosis of mediastinal lymph node metastasis of non-small cell lung cancer / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the value of positron emission tomographic-computed tomographic scanning (PET/CT) in the diagnosis of mediastinal lymph node metastasis in patients with non-small cell lung cancer and the application of PET/CT in the clinical staging of NSCLC.</p><p><b>METHODS</b>A hundred and fifty-eight patients with NSCLC undergoing surgical resection and mediastinoscopy received preoperative examinations with PET/CT. All the patients underwent mediastinal lymph node dissection or sampling, and the pathological results were compared with the imaging findings. The diagnostic sensitivity, specificity, positive and negative predictive values, and accuracy of CT and PET/CT were compared.</p><p><b>RESULTS</b>Final histology was available for 937 lymph node samples (N1, N2, and N3) from 158 patients during mediastinoscopy or surgical resection. The sensitivity, specificity, and positive and negative predictive values of CT for identifying mediastinal lymph node involvement were 51.0%, 76.1%, 49.0%, and 77.6%, respectively, with an diagnostic accuracy of 68.4%. The sensitivity, specificity, and positive and negative predictive values of PET/CT were 83.7%, 89.0%, 77.4%, and 92.4%, respectively, with a diagnostic accuracy of 87.3%.</p><p><b>CONCLUSION</b>Mediastinoscopy is essential for patients with positive findings of mediastinal lymph node involvement by PET/CT, but might not be necessary in negative patients.</p>

Reverse 201Tl myocardial redistribution induced by coronary artery spasm / 中华核医学杂志

Objective To investigate the mechanism of reverse redistribution (RR) on dipyridamole 201Tl myocardial perfusion studies in the patients with coronary artery spasm. Methods Twenty-six patients with coronary artery spasm and presented as RR on dipyridamole 201Tl myocardial perfusion studies were enlisted as RR group, while other 16 patients with no coronary artery stenosis nor RR were enlisted as control group. Dipyridamole test was repeated during coronary angiography. Corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and TIMI myocardial perfusion grade (TMPG) were measured at RR related and non-RR related coronary arteries before and after dipyridamole infusion respectively.All of the data were analyzed by Student's t-test orχ2-test and correlation analysis. Results Coronary artery angiography showed slower blood flow and lower myocardial perfusion in RR related vessels when compared with non-RR related vessels in RR group, but there was no significant difference among the main coronary arteries in control group. The perfusion defects of RR area at rest were positively related to slowerblood velocity at corresponding coronary arteries ( r = 0.79, t = 10.18, P ＜ 0.001 ). In RR related vessels,CTFC were (36 ±6) frames and (26 ±7) frames (t =4.15, P ＜0.01 ), while TMPG were (2.02 ±0.39)grades and (2.92 ± 0.12) grades ( t = 2.25, P ＜ 0.05 ) before and after dipyridamole infusion, respectively.In non-RR related vessels, CTFC were (29 ±7) frames and (25 ±5) frames (t =2.31, P ＜0.05), while TMPG were (2.56 ± 0.31 ) grades and (2.96 ± 0.06) grades ( t = 2.17, P ＜ 0.05 ) before and after dipyridamole infusion, respectively. However, there were no significant changes of CTFC and TMPG before and after dipyridamole infusion in control group ( t = 0.932, 0.867, respectively, both P ＞ 0.05 ). Conclusion RR is related to the decreased blood flow and myocardial perfusion induced by coronary artery spasm at rest,which may be improved by stress test such as intravenous dipyridamole infusion.

PET/CT for the diagnosis of sarcoidosis and analysis on reasons of misdiagnosis / 中华核医学杂志

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) Extrathoracic 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 lynphadenopathy can be difficult.Whole-body PET/CT may be helpful in the differentiation of the two diseases.

Relationship between fluorodeoxyglucose uptake and overexpression of glucose transport protein 1 and hexokinase-Ⅱ in early-stage nasopharyngeal carcinoma / 中华核医学杂志

Objective To discuss the molecular mechanism of 18F-fluorodeoxyglucose (FDG) uptake in tumor and to assess its value to identify pathologic type and cancer staging in patients with earlystage nasopharyngeal carcinoma.Methods Forty patients with nasopharyngeal carcinoma of early-stage,including 12 cases with T1 stage and 28 cases with T2 stage, underwent FDG PET imaging.The maximum standardized uptake value ( SUVmax ) and mean standardized uptake value ( SUVmean ) of FDG uptake of each patient were measured and compared between T1 and T2 stage by t-test.The expression of glucose transport protein 1 ( Glut1 ) and hexokinase- Ⅱ ( HK- Ⅱ ) of each case was measured in paraffin sections by streptavidin-perosidase (SP) immunohistochemistry.The positive expression rate of Glut1 and HK- Ⅱ was calculated and compared between T1 and T2 by x2 test.Meanwhile, the correlation between the expression of Glut1 or HK-Ⅱ and the SUVmax was tested by Pearson analysis.Results The SUVmax and SUVmean in 40 patients were 9.45 ± 1.87 and 6.04 ± 1.09, respectively.The SUVmax of patients with T1 stage (8.95 ± 1.91 ) was significantly lower (t =4.46, P＜0.001 ) than that of patients with T2 stage (11.55 ± 1.70), and the SUVmean of patients with T1 stage (5.61 ± 1.08) was significantly lower ( t = 6.76, P ＜ 0.001 ) than that of patients with T2 stage (7.98 ± 1.10) too.Among 40 patients, all patients showed positive expression of Glut1 and HK-Ⅱ , and the positive expression rate of Glut1 and HK-Ⅱ was ( 45.2 ± 10.9 )% and ( 68.3 ±9.5)%, respectively.The positive expression rate of Glut1 was (38.4 ±8.1)% in T1 stage and (49.7 ±12.6)% in T2 stage, which displayed no difference (x2 =40.58, P＞0.05), but the HK-Ⅱ positive expression rate showed significant difference (x2 =58.71, P＜0.05) between T1 stage (60.1 ±11.1)% and T2 stage (77.9 ± 14.7 )%.The correlation analysis indicated that there was low-degree positive correlation (r =0.369, P=0.019) between the SUVmax and Glut1 expression, and there was medium-degree positive correlation (r = 0.549, P = 0.001 ) between the SUVmax and HK-Ⅱ expression.Conclusion Expression of Glut1 and HK-Ⅱ was positively correlated with FDG uptake in patients with early-stage nasopharyngeal carcinoma.

Relationship between fluorodeoxyglucose uptake and vascular endothelial growth factor in early-stage nasophygeal carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the overexpression of vascular endothelial growth factor (VEGF) and fluorine-18 fluorodeoxyglucose (FDG) uptake in early-stage nasopharyngeal carcinoma (NPC) and evaluate their relationship.</p><p><b>METHODS</b>FDG positron emission tomography (PET) was performed in forty patients with stage I and stage II NPC. The maximum and mean standard uptake values (SUVmax and SUVmean, respectively) were measured in each patient, and the expression of VEGF was measured on paraffin sections using immunohistochemistry.</p><p><b>RESULTS</b>The FDG uptake in the patients were 9.45-/+1.87 (SUVmax) and 6.04-/+1.09 (SUVmean), 8.95-/+1.91 (SUVmax) and 6.04-/+1.09 (SUVmean) in stage I patients, and 11.55-/+1.70 (SUVmax) and 7.98-/+1.1 (SUVmean) in stage II patients. The FDG uptake of stage II patients was higher than that of stage I patients. The FDG uptake of non-keratinizing differentiated carcinoma was 9.74-/+1.82 (SUVmax) and 6.82-/+1.23 (SUVmean) and 10.44-/+2.16 (SUVmax) and 6.68-/+1.35 (SUVmean) in non-keratinizing undifferentiated carcinoma, showing no significant differences between them (SUVmax: t=1.230, P>0.05; SUVmean: t=0.346, P>0.05). The VEGF-positive cells were 60.80% in the tumor. A correlation between VEGF expression and FDG uptake in he tumor was noted (r=0.460, P=0.03).</p><p><b>CONCLUSION</b>VEGF overexpression is correlated to FDG uptake in patients with early-stage NPC. The SUV value reflects the glucose metabolism of NPC, and also shows the degree of oxygen insufficiency in the tumor tissue.</p>

Detection of malignant lymphoma with invasion in liver and spleen using PET/CT imaging / 中华核医学杂志

Objective The detection of malignant lymphoma with invasion in liver and spleen using PET/CT has not been well documented in the literature. This study aimed to investigate the usefulness of PET/CT in this regard and to compare it with plain CT. Methods Forty-one pathologically confirmed malignant lymphoma patients with liver and spleen invasion were recruited into this study. Among all patients, there were 38 non-Hodgkin's lymphoma (NHL), 2 Hodgkin's lymphoma (HL) and 1 gastric mucosa associated lymphoma. PET/CT imaging was recorded 1h after injection of 296～444 MBq 18F-fluorodeoxyglucose (FDG). Results (1) There were 30(30/41) patients with liver invasion, including hepatic nodules, mass and portal nodes. The mass was large to invade surrounding liver parenchyma. (2) There were 23(23/41) patients with spleen invasion. The spleen was enlarged and demonstrated diffused hyper-metabolism. (3) Other invasion included: lung (n=13), cortical bone and marrow (n=12), stomach (n=9), pleural (n=6), and subcutaneous soft tissue (n=5) and so on. Conclusion PET/CT could accurately diagnose the invasion in liver and spleen of malignant lymphoma, which was of potential role on the diagnosis and staging of lymphoma.

Analysis of standard uptake values of 18F-FDG PET/CT in relation to pathological classification and clinical staging of nasopharyngeal carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the relation of the standard uptake values (SUV) of 18F-fluorodexygl-gucose (18F-FDG) PET/CT and the pathological classification and clinical staging of nasopharyngeal carcinoma (NPC).</p><p><b>METHOD</b>Whole body 18F-FDG PET imaging was performed in 32 patients with pathologically confirmed NPC, who received no previous treatment. The regions of interest (ROI) covering the pharyngeal and cervical lesions were defined along the margins of the lesion, and the lesion volume and the SUVs were calculated.</p><p><b>RESULTS</b>The SUVs in stage I, II, III, and IV patients were 4.50-/+0.42, 5.62-/+1.44, 7.33-/+1.50, and 8.24-/+2.16, respectively, showing significant differences between them (P < 0.05). In patients in stage T1, T2, T3, and T4, the SUVs increased significantly in advanced stageds (2.56-/+1.05, 3.72-/+0.60, 6.87-/+1.07, and 9.70-/+0.70, respectively, P < 0.05). The SUVs were not significantly different in patients in stages N1, N2, and N3, differed significantly between lymph nodes > 6 cm in size and those < or = 6 cm (5.92-/+1.51 vs 3.48-/+1.31, P < 0.05). The SUV in poorly differentiated squamous carcinoma was significantly lower than that in undifferentiated carcinoma (5.58-/+1.48 vs 8.41-/+1.71, F = 1.3323, P = 0.01).</p><p><b>CONCLUSIONS</b>The SUV is not associated with the clinical staging of NPC, but is correlated to the T staging of NPC. Though irrelevant to the N staging of NPC, the SUV is correlated to the size of the lymph nodes, and also related to the degree of differentiation of NPC.</p>

PET/CT-based classification of delayed radiation encephalopathy following radiotherapy for nasopharyngeal carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate positron-emission tomography-computed tomography (PET/CT) findings of radiation encephalopathy (RE) following radiotherapy for nasopharyngeal carcinoma (NPC), observe the metabolic changes of the compromised brain tissues, and postulate the clinical classification of RE to provide reference for its diagnosis.</p><p><b>METHODS</b>This study included 53 pathologically confirmed NPC patients who received previous radical radiotherapy, and the diagnosis of RE was established according to the clinical manifestations and CT/PET findings. All the patients underwent PET/CT whole-body and head scans, and the image data were evaluated along with the clinical data of the patients.</p><p><b>RESULTS</b>RE most frequently involved the lateral or bilateral inferior temporal lobes. PET identified hypometabolic changes in the bilateral temporal lobes of 35 patients (70 lobes) and in the lateral temporal lobe of 18 patients (18 lobes). According to the PET/CT findings, the lesions were classified into 3 types, namely the oedema type (56 temporal lobes), liquefactive necrosis type (10 temporal lobes), and atrophic calcification type (22 temporal lobes). One patient with oedema type lesion received neurotrophic treatment and recovered completely with normal brain tissue density and metabolism, but the oedema type lesions in 2 patients progressed into to atrophic calcification type; the liquefactive necrotic lesions in another 2 patients also progressed into atrophic calcification type.</p><p><b>CONCLUSION</b>RE patients exhibit significant hypometabolic changes in the inferior temporal lobe on PET. According to the findings by PET/CT, RE can be classified into the oedema type, liquefactive necrosis type, and atrophic calcification type, and lesions of the former two types may progress into the third type.</p>

PET/CT imaging of delayed radiation encephalopathy following radiotherapy for nasopharyngeal carcinoma / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>With the significant improvement in the survival of patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy and the growing availability of the sophisticated imaging modalities, the number of radiation encephalopathy (RE) cases relating to NPC radiotherapy is increasing. In this study, we investigated the metabolic and density changes of the compromised brain tissues during delayed RE using a positron-emission tomography-computed tomography (PET/CT) to provide clinical evidences for the diagnosis of delayed RE following radiotherapy for NPC.</p><p><b>METHODS</b>The PET/CT manifestations and the clinical data of 53 pathologically confirmed NPC patients with delayed RE following radical radiotherapy and 15 healthy volunteers were investigated. The standardized uptake values (SUV) of the bilateral temporal lobes, the occipital lobe and the brain stem were measured respectively; and then the metabolic reduction rate of 88 temporal lobes and 13 brain stems were calculated for a statistical comparison between the two groups.</p><p><b>RESULTS</b>The earliest case of delayed RE in the investigated patients occurred 1.5 years after radiotherapy. Delayed RE frequently involved the inferior temporal lobe. For patients with delayed RE confirmed by clinical symptoms and imaging findings, PET maintained a 100% coincidence rate with CT; however, in the 25 temporal lobes of the 35 delayed RE patients, PET revealed obvious hypometabolic changes whereas CT displayed normal density. The incidence of brain stem metabolic reductions was 24.5% (13/53) in the investigated patients, including 4 patients with hypometabolic changes shown by PET and negative finding shown by CT. The incidence of granuloma adjacent to the hypometabolic region in the temporal lobe was 12.5% (11/88).</p><p><b>CONCLUSION</b>Delayed RE patients exhibit significant hypometabolic changes in the inferior temporal lobe, captured by PET much earlier than by CT. PET/CT offers a valuable means for the diagnosis of delayed RE in subacute stages and granuloma formation.</p>