PET predicts prognosis after 1 cycle of chemotherapy in aggressive lymphoma and Hodgkin's disease.

Early identification of chemotherapy-refractory lymphoma patients provides a basis for alternative treatment strategies. Metabolic imaging with (18)F-FDG PET offers functional tissue characterization that is useful for assessing response to therapy. Our objective was to determine the predictive value of (18)F-FDG PET early during chemotherapy (after 1 cycle) and at the completion of chemotherapy for subsequent progression-free survival (PFS) in patients with aggressive non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD). METHODS: (18)F-FDG PET (dual-head coincidence camera with attenuation correction) was performed before and after 1 cycle of chemotherapy on 30 patients (17 NHL, 13 HD; mean age, 52.3 +/- 16.0 y). For 23 of the 30 patients, (18)F-FDG PET data were also obtained after the completion of chemotherapy. The patients had a median follow-up of 19 mo (range, 18-24 mo). Follow-up of PFS was compared between patients with positive and negative (18)F-FDG PET results obtained after the first cycle of chemotherapy and at the completion of chemotherapy. RESULTS: Positive (18)F-FDG PET results obtained both after the first cycle and at the completion of therapy were associated with a shorter PFS (median, 5 and 0 mo, respectively) than were negative (18)F-FDG PET results (PFS medians not reached). A statistically significant difference in PFS between positive and negative (18)F-FDG PET results was obtained both after the first cycle and at the completion of chemotherapy (P < or = 0.001). The PFS and (18)F-FDG PET results obtained after the first cycle correlated better than those obtained after the completion of chemotherapy (r(2) = 0.45 vs. 0.17). (18)F-FDG PET had more false-negative results after the last cycle (6/17 cases, or 35%) than after the first cycle (2/13 cases, or 15%). Thus, (18)F-FDG PET had greater sensitivity and positive predictive values after the first cycle (82% vs. 45.5% and 90% vs. 83%, respectively) than after the last cycle. CONCLUSION: (18)F-FDG PET after 1 cycle of chemotherapy is predictive of 18-mo outcome in patients with aggressive NHL and HD and may earlier identify patients who would benefit from more intensive treatment programs.     

18F-FDG PET显像在乳腺癌中的应用

^18F-FDG(^18F-氟脱氧葡萄糖)PET(正电子发射型计算断层显像)是反映恶性肿瘤代谢特征的一种无创性的功能显像方法。在绝大多数肿瘤中均得到广泛应用。本文通过对国内外乳腺癌^18F-FDG PET。显像的文章进行全面综合分析，旨在探讨^18F-FDG PET显像在乳腺癌中的应用原理及其临床应用价值。与传统影像学相比，^18F-FDG PET。显像能够更为准确地发现原发性乳腺癌远处转移和局部复发，可以在治疗早期及时评价化疗疗效以指导临床治疗。对于原发性乳腺癌的诊断。PET显像不作为首选检查。但对于临床检查或常规影像检查难以进行或无明确结论的病人。PET显像可以作为其乳腺肿块定性诊断的最佳选择。     

Early prediction of response to chemotherapy and survival in malignant pleural mesothelioma using a novel semiautomated 3-dimensional volume-based analysis of serial 18F-FDG PET scans.

The aim of chemotherapy for mesothelioma is to palliate symptoms and improve survival. Measuring response using CT is challenging because of the circumferential tumor growth pattern. This study aims to evaluate the role of serial (18)F-FDG PET in the assessment of response to chemotherapy in patients with mesothelioma. METHODS: Patients were prospectively recruited and underwent both (18)F-FDG PET and conventional radiological response assessment before and after 1 cycle of chemotherapy. Quantitative volume-based (18)F-FDG PET analysis was performed to obtain the total glycolytic volume (TGV) of the tumor. Survival outcomes were measured. RESULTS: Twenty-three patients were suitable for both radiological and (18)F-FDG PET analysis, of whom 20 had CT measurable disease. After 1 cycle of chemotherapy, 7 patients attained a partial response and 13 had stable disease on CT assessment by modified RECIST (Response Evaluation Criteria in Solid Tumors) criteria. In the 7 patients with radiological partial response, the median TGV on quantitative PET analysis fell to 30% of baseline (range, 11%-71%). After 1 cycle of chemotherapy, Cox regression analysis demonstrated a statistically significant relationship between a fall in TGV and improved patient survival (P = 0.015). Neither a reduction in the maximum standardized uptake value (P = 0.097) nor CT (P = 0.131) demonstrated a statistically significant association with patient survival. CONCLUSION: Semiquantitative (18)F-FDG PET using the volume-based parameter of TGV is feasible in mesothelioma and may predict response to chemotherapy and patient survival after 1 cycle of treatment. Therefore, metabolic imaging has the potential to improve the care of patients receiving chemotherapy for mesothelioma by the early identification of responding patients. This technology may also be useful in the assessment of new systemic treatments for mesothelioma.     

Tumor localization of 16beta-18F-fluoro-5alpha-dihydrotestosterone versus 18F-FDG in patients with progressive, metastatic prostate cancer.

This trial was an initial assessment of the feasibility, in vivo targeting, and biokinetics of 16beta-(18)F-fluoro-5alpha-dihydrotestosterone ((18)F-FDHT) PET in patients with metastatic prostate cancer to assess androgen receptor expression. METHODS: Seven patients with progressive clinically metastatic prostate cancer underwent (18)F-FDG and (18)F-FDHT PET scans in addition to conventional imaging methods. Three patients had their studies repeated 1 mo later, 2 while on testosterone therapy, and the third after treatment with 17-allylamino-17-demethoxygeldanamycin (17-AAG). High-pressure liquid radiochromatography was used to separate (18)F-FDHT from radiolabeled metabolites. Lesion-by-lesion comparisons between the (18)F-FDHT, (18)F-FDG, and conventional imaging methods were performed. RESULTS: Metabolism of (18)F-FDHT was rapid, with 80% conversion within 10 min to radiolabeled metabolites that circulated bound to plasma proteins. Tumor uptake was rapid and tumor retention was prolonged. Fifty-nine lesions were identified by conventional imaging methods. (18)F-FDG PET was positive in 57 of 59 lesions (97%), with an average lesion maximum standardized uptake value (SUV(max)) = 5.22. (18)F-FDHT PET was positive in 46 of 59 lesions (78%), with the average positive lesion SUV(max) = 5.28. Treatment with testosterone resulted in diminished (18)F-FDHT uptake at the tumor site. CONCLUSION: (18)F-FDHT localizes to tumor sites in patients with progressive clinically metastatic prostate cancer and may be a promising agent to analyze antigen receptors and their impact on the clinical management of prostate cancer.     

Evaluation of head and neck cancer with 18F-FDG PET: a comparison with conventional methods

The aim of this study was to evaluate the usefulness of 18F-FDG PET in the diagnosis and staging of primary and recurrent malignant head and neck tumours in comparison with conventional imaging methods [including ultrasonography, radiography, computed tomography (CT) and magnetic resonance imaging (MRI)], physical examination, panendoscopy and biopsies in clinical routine. A total of 54 patients (13 female, 41 male, age 61.3+/-12 years) were investigated retrospectively. Three groups were formed. In group I, 18F-FDG PET was performed in 15 patients to detect unknown primary cancers. In group II, 24 studies were obtained for preoperative staging of proven head and neck cancer. In group III, 18F-FDG PET was used in 15 patients to monitor tumour recurrence after radiotherapy and/or chemotherapy. In all patients, imaging was obtained at 70 min after the intravenous administration of 180 MBq 18F-FDG. In 11 of the 15 patients in group I, the primary cancer could be found with 18F-FDG, yielding a detection rate of 73.3%. In 4 of the 15 patients, CT findings were also suggestive of the primary cancer but were nonetheless equivocal. In these patients, 18F-FDG showed increased 18F-FDG uptake by the primary tumour, which was confirmed by histology. One patient had recurrence of breast carcinoma that could not be detected with 18F-FDG PET, but was detected by CT. In three cases, the primary cancer could not be found with any imaging method. Among the 24 patients in group II investigated for staging purposes, 18F-FDG PET detected a total of 13 local and three distant lymph node metastases, whereas the conventional imaging methods detected only nine local and one distant lymph node metastases. The results of 18F-FDG PET led to an upstaging in 5/24 (20.8%) patients. The conventional imaging methods were false positive in 5/24 (20.8%). There was one false positive result using 18F-FDG PET. Among the 15 patients of group III with suspected recurrence after radiotherapy and/or chemotherapy, 18F-FDG was true positive in 7/15 (46.6%) and true negative in 4/15 (26.6%). The conventional imaging methods were true positive in 5/15 (33.3%) and true negative in 4/15 (26.6%). One false negative (6.6%) and three false positive findings (20%) on 18F-FDG PET were due to inflamed tissue. The conventional imaging methods were false positive in three (20%) and false negative in three cases (20%). It is concluded that in comparison to conventional diagnostic methods, 18F-FDG PET provides additional and clinically relevant information in the detection of primary and metastatic carcinomas as well as in the early detection of recurrent or persistent head and neck cancer after radiotherapy and/or chemotherapy. 18F-FDG PET should therefore be performed early in clinical routine, usually before CT or MRI.     

^18F—FDG PET／CT评价弥漫性大B细胞淋巴瘤化疗中期的治疗反应

目的探讨^18F-FDGPET／CT评价弥漫性大B细胞淋巴瘤（DLBCL）患者化疗中期治疗反应的价值。方法DLBCL初诊患者53例,采用环磷酰胺＋阿霉素＋长春新碱＋泼尼松（CHOP）或利妥苷单克隆抗体＋环磷酰胺＋阿霉素＋长春新碱＋泼尼松（R-CHOP）方案化疗,分别于化疗前和化疗中期（4个疗程后）进行^18F-FDGPET／CT显像。根据肿瘤对化疗的反应将病例分为完全反应组、部分反应组和无反应组,比较3组患者的完全缓解率。用SPSS13．0软件进行统计学分析,完全缓解率的比较用x2检验。结果完全反应组、部分反应组和无反应组的临床完全缓解率分别为88．5％（23／26）、73．3％（11／15）和8．3％（1／12）,3组问差异有统计学意义（X2=23．548,P=0．000）。完全反应组、部分反应组的完全缓解率高于无反应组（X2=22．656,P=0．000和x2=11．407,P=0．001）。结论DLBCL患者化疗中期^18F-FDG PET／CT显像有助于预测其化疗疗效。     

Usefulness of whole-body (18)F-FDG PET in patients with suspected metastatic brain tumors.

The aim of this study was to evaluate the diagnostic value of whole-body (18)F-FDG PET imaging in the differentiation of metastatic brain tumor from primary brain tumor and in the localization of the primary lesion in patients with metastatic brain tumor. METHODS: The subjects consisted of 127 patients (77 men, 50 women; mean age +/- SD, 55 +/- 12 y) with brain masses that were suspected to be metastatic brain tumors on radiologic studies: 77 with confirmed metastatic brain tumor and 50 with primary brain tumor. Whole-body (18)F-FDG PET was performed on all patients. When the abnormal lesion was detected outside the brain, we interpreted the brain lesion as metastatic brain tumor. RESULTS: In 61 of the 77 patients with metastatic brain tumor, primary lesions were detected using whole-body (18)F-FDG PET. Of the remaining 16 patients (all false-negative cases), 7 were classified as metastases of unknown origin. In 47 of the 50 patients with primary brain tumor, whole-body (18)F-FDG PET did not show any other abnormal lesions. The sensitivity, specificity, positive and negative predictive values, and accuracy of PET for the detection of primary origin were 79.2%, 94.0%, 95.3%, 74.6%, and 85.0%, respectively. The most common primary origin of metastatic brain tumors on PET examination was lung cancer (48/61, 78.7%). The concordance rate between (18)F-FDG PET and conventional radiologic work-up was 80% in identifying primary lesion. Unknown bone or bone marrow metastases and unsuspected distant metastases were found in 14 patients (18%) and 24 patients (31%), respectively, on PET examination. CONCLUSION: Screening the patients with suspected metastatic brain tumors using whole-body (18)F-FDG PET could be helpful in differentiating metastatic brain tumor from primary brain tumor and in detecting the primary lesion.     

Evaluation of head and neck cancer with 18F-FDG PET: a comparison with conventional methods

The aim of this study was to evaluate the usefulness of ¹⁸F-FDG PET in the diagnosis and staging of primary and recurrent malignant head and neck tumours in comparison with conventional imaging methods [including ultrasonography, radiography, computed tomography (CT) and magnetic resonance imaging (MRI)], physical examination, panendoscopy and biopsies in clinical routine. A total of 54 patients (13 female, 41 male, age 61.3ᆠ years) were investigated retrospectively. Three groups were formed. In group I, ¹⁸F-FDG PET was performed in 15 patients to detect unknown primary cancers. In group II, 24 studies were obtained for preoperative staging of proven head and neck cancer. In group III, ¹⁸F-FDG PET was used in 15 patients to monitor tumour recurrence after radiotherapy and/or chemotherapy. In all patients, imaging was obtained at 70 min after the intravenous administration of 180 MBq ¹⁸F-FDG. In 11 of the 15 patients in group I, the primary cancer could be found with ¹⁸F-FDG, yielding a detection rate of 73.3%. In 4 of the 15 patients, CT findings were also suggestive of the primary cancer but were nonetheless equivocal. In these patients, ¹⁸F-FDG showed increased ¹⁸F-FDG uptake by the primary tumour, which was confirmed by histology. One patient had recurrence of breast carcinoma that could not be detected with ¹⁸F-FDG PET, but was detected by CT. In three cases, the primary cancer could not be found with any imaging method. Among the 24 patients in group II investigated for staging purposes, ¹⁸F-FDG PET detected a total of 13 local and three distant lymph node metastases, whereas the conventional imaging methods detected only nine local and one distant lymph node metastases. The results of ¹⁸F-FDG PET led to an upstaging in 5/24 (20.8%) patients. The conventional imaging methods were false positive in 5/24 (20.8%). There was one false positive result using ¹⁸F-FDG PET. Among the 15 patients of group III with suspected recurrence after radiotherapy and/or chemotherapy, ¹⁸F-FDG was true positive in 7/15 (46.6%) and true negative in 4/15 (26.6%). The conventional imaging methods were true positive in 5/15 (33.3%) and true negative in 4/15 (26.6%). One false negative (6.6%) and three false positive findings (20%) on ¹⁸F-FDG PET were due to inflamed tissue. The conventional imaging methods were false positive in three (20%) and false negative in three cases (20%). It is concluded that in comparison to conventional diagnostic methods, ¹⁸F-FDG PET provides additional and clinically relevant information in the detection of primary and metastatic carcinomas as well as in the early detection of recurrent or persistent head and neck cancer after radiotherapy and/or chemotherapy. ¹⁸F-FDG PET should therefore be performed early in clinical routine, usually before CT or MRI.     

18F-FDG PET in detecting metastatic infectious disease.

Timely identification of metastatic complications of bloodstream infections due to spreading of the microorganisms to distant sites, although critical, is often difficult. As 18F-FDG accumulates in activated leukocytes in infectious lesions, 18F-FDG PET represents a promising imaging technique in these patients. The aim of this study was to assess the value of 18F-FDG PET in detecting infectious foci in patients at high risk of metastatic complications. METHODS: The results of all 18F-FDG PET scans ordered because of suspected metastatic infection from October 1998 to September 2004 were analyzed retrospectively. These results were compared with conventional investigation techniques and the final clinical diagnosis. RESULTS: The results of 40 18F-FDG PET scans were evaluated. In 60% of all episodes, Gram-positive bacteria were cultured, in 18% Gram-negative bacteria, in 20% Candida spp., and in 3% the infection was polymicrobial. Metastatic complications were diagnosed in 75% of all episodes. A median number of 4 diagnostic procedures to search for metastatic infection had been performed before 18F-FDG PET was ordered. 18F-FDG PET diagnosed a clinically relevant new focus in 45% of cases and confirmed abnormalities already diagnosed in 30% of cases. The positive predictive value of 18F-FDG PET was 91% and the negative predictive value was 100%. CONCLUSION: 18F-FDG PET is a valuable imaging technique in patients at high risk of metastatic infectious disease, even when the results of other diagnostic procedures are normal.     

Evaluation of therapy for lymphoma

Positron emission tomography (PET) using (18)F-fluorodeoxyglucose ((18)F-FDG) is the best noninvasive imaging technique for to assess response in patients suffering from lymphoma. Early response evaluation ("interim PET") after one, a few cycles, or at midtreatment can predict response, progression-free survival, and overall survival. We calculated from data of 7 studies an overall sensitivity to predict treatment failure of 79%, a specificity of 92%, a positive predictive value (PPV) of 90%, a negative predictive value (NPV) of 81%, and an accuracy of 85%. Although it is not yet indicated to change patient management based on residual (18)F-FDG uptake on interim scan in chemotherapy-sensitive patients, prospective studies evaluating the role of an interim PET in patient management clearly are warranted. (18)F-FDG PET also has an important prognostic role in relapsing patients after reinduction chemotherapy before high-dose chemotherapy (HCT) followed by autologous stem cell transplantation (ASCT). However, all chemotherapy-sensitive patients remain candidates for HCT followed by ASCT, even if (18)F-FDG PET showed residual (18)F-FDG uptake. We calculated from data of 3 studies an overestimated risk of relapse in 16% of all PET-positive patients. Some patients with residual (18)F-FDG uptake will have a good outcome after HCT followed by ASCT. (18)F-FDG PET is the imaging technique of choice for end-of-treatment evaluation. However, (18)F-FDG is not specific for tumoral tissue. Active inflammatory lesions and infectious processes can be falsely interpreted as malignant residual cells. However, a negative (18)F-FDG PET cannot exclude minimal residual disease. Consequently, it is always indicated to correlate PET findings with clinical data, other imaging modalities, and/or a biopsy. We calculated, from data of 17 studies in end-of-treatment evaluation, a sensitivity of 76%, a specificity of 94%, a PPV of 82%, a NPV 92%, and an accuracy of 89%.     

Prospective comparison of 18F-FDG PET with conventional imaging modalities (MRI, CT, and 67Ga scintigraphy) in assessment of combined intraarterial chemotherapy and radiotherapy for head and neck carcinoma.

To preserve the oral organs and functions in patients with head and neck carcinoma, accurate determination of the appropriate treatment after neoadjuvant chemotherapy and radiotherapy is of critical importance. We evaluated the diagnostic accuracy of (18)F-FDG PET relative to that of other conventional imaging modalities in the assessment of therapeutic response after combined intraarterial chemotherapy and radiotherapy as an organ preservation protocol. METHODS: The study was prospectively performed on 23 consecutive patients with head and neck squamous cell carcinoma who completed the treatment regimen and underwent 2 (18)F-FDG PET studies before and after neoadjuvant chemoradiotherapy. (67)Ga scintigraphy (only before therapy) as well as MRI and CT (both before and after therapy) were also performed. All images were blindly and independently interpreted without knowledge of histologic findings. The level of confidence in image interpretation was graded by means of a 5-point rating system (0 = definitely no tumor to 4 = definite tumor). RESULTS: Before treatment, (18)F-FDG PET detected primary tumors in all 23 patients and was more sensitive (100%) than MRI (18/23; 78.3%), CT (15/22; 68.2%), and (67)Ga scintigraphy (8/20; 40%), with a confidence level of 3 or 4 as a positive tumor finding. After chemoradiotherapy, residual tumors were histologically confirmed in 4 patients (pathologic complete response rate, 19/23; 82.6%). Although posttreatment (18)F-FDG PET showed almost equal sensitivity (4/4; 100%) compared with MRI (3/3; 100%) or CT (3/4; 75%), its specificity (17/19; 89.5%) was superior to MRI (7/17, 41.2%) and to CT (10/17; 58.8%) for primary lesions. Regarding metastases to neck lymph nodes, only specificity for posttreatment images was calculated because no metastasis was confirmed in any patients after treatment. Six subjects had (18)F-FDG PET-positive lymph nodes, which had pathologically no tumor cells and suggested an inflammatory reactive change after therapy. Therefore, the specificity of posttreatment (18)F-FDG PET (17/23; 73.9%) was almost identical to that of MRI (17/20; 85%) and CT (16/21; 76.2%) for neck metastasis. With combined chemoradiotherapy monitored with (18)F-FDG PET, 8 patients avoided surgery and the remaining 15 patients underwent a reduced form of surgery. CONCLUSION: (18)F-FDG PET facilitates differentiation of residual tumors from treatment-related changes after chemoradiotherapy, which may be occasionally difficult to characterize by anatomic images. (18)F-FDG PET has a clinical impact for the management of patients with head and neck cancers after neoadjuvant chemoradiotherapy by optimizing surgical treatment for each patient and contributes to the improvement of the patient's quality of life.     

18F-FDG PET在淋巴瘤分期和治疗反应评价中的价值

18F-FDG PET显像对淋巴瘤的诊断、分期作用显著,对淋巴瘤病灶的探测灵敏度和准确性高于67Ga显像.在化疗过程中和化疗后持续18F-FDG PET阳性对预测复发有高灵敏度.治疗结束时18F-FDG PET阴性提示患者预后好.与其他常规显像相比,18F-FDG PET在监测淋巴瘤疗效、判断治疗反应方面有独特优势.     

The role of 18F-FDG PET in staging and early prediction of response to therapy of recurrent gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are gaining the interest of researchers because of impressive metabolic response to the targeted molecular therapeutic drug imatinib mesylate. Initial reports suggest an impressive role for (18)F-FDG PET in follow-up of therapy for these tumors. However, the role of (18)F-FDG PET versus that of CT has not been established. Therefore, we compared the roles of (18)F-FDG PET and CT in staging and evaluation of early response to imatinib mesylate therapy in recurrent or metastatic GIST. METHODS: The study included 54 patients who underwent (18)F-FDG PET and CT scans within 3 wk before initiation of imatinib mesylate therapy. Forty-nine of these patients underwent repeat scans 2 mo after therapy. The numbers of sites or organs containing lesions on (18)F-FDG PET and CT scans were compared. Corresponding lesions on (18)F-FDG PET and CT scans or those confirmed to be malignant in appearance by other imaging modalities or on follow-up were considered true positives. Lesions seen on (18)F-FDG PET or CT scans but not seen or confirmed to be of benign appearance with other imaging modalities or on follow-up were considered false positives. Measurements of the maximum standard uptake value (SUV) on (18)F-FDG PET scans and tumor size on CT scans were used for quantitative evaluation of early tumor response to therapy. RESULTS: A total of 122 and 114 sites and/or organs were involved on pretherapy (18)F-FDG PET and CT scans, respectively. The sensitivity and positive predictive values (PPVs) for CT were 93% and 100%; whereas these values for (18)F-FDG PET were 86% and 98%. However, the differences between these values for CT and (18)F-FDG PET were not statistically significant (P = 0.27 for sensitivity and 0.25 for PPV). This suggests comparable performance of (18)F-FDG PET and CT in staging GISTs. Repeat scans at 2 mo after therapy showed agreement between (18)F-FDG PET and CT scans in 71.4% of patients (57.1% having a good response to therapy and 14.3% lacking a response). Discrepant results between (18)F-FDG PET and CT were recorded for 28.6% of the patients. (18)F-FDG PET predicted response to therapy earlier than did CT in 22.5% of patients during a longer follow-up interval (4-16 mo), whereas CT predicted lack of response to therapy earlier than (18)F-FDG PET in 4.1%. One patient did not undergo long-term follow-up. These findings suggest that (18)F-FDG PET is superior to CT in predicting early response to therapy in recurrent or metastatic GIST patients. CONCLUSION: The performances of (18)F-FDG PET and CT are comparable in staging GISTs before initiation of imatinib mesylate therapy. However, (18)F-FDG PET is superior to CT in predicting early response to therapy. Thus, (18)F-FDG PET is a better guide for imatinib mesylate therapy.     

18-FDG PET/CT在肝癌治疗后AFP升高患者中的应用

目的 探讨18F-脱氧葡萄糖(FDG)PET/CT检测肝癌治疗后甲胎蛋白(AFP)升高患者肿瘤复发和(或)转移病灶的价值.方法 原发性肝细胞癌治疗后血清AFP升高患者123例,皆行全身18F-FDG PET/CT显像.所有图像经图像融合后,进行PET/CT融合图像、PET图像和CT图像帧对帧对比分析.肿瘤复发和(或)转移病灶根据病理检查结果、多种影像学诊断及临床随访而确诊.随访时间均>6个月.采用SPSS 11.5软件进行统计学处理,进行X2检验.结果 123例患者中,明确诊断肿瘤复发和(或)转移者111例.18F-FDG PET显像诊断肿瘤复发和(或)转移78例,其灵敏度为70.3%(78/111);18F.FDG PET/CT显像诊断肿瘤复发和(或)转移97例,灵敏度提高至87.4%(97/111,χ2=9.744,P=0.002).18F.FDG PET/CT诊断肝癌复发和转移的特异性、准确性、阳性预测值和阴性预测值分别为83.3%(10/12)、87.0%(107/123)、98.0%(97/99)和41.7%(10/24).9例高分化肝细胞癌患者均确诊为肿瘤复发和(或)转移,18F-FDG PET/CT显像诊断其肿瘤复发和(或)转移5例,灵敏度(5/9)明显低于总体灵敏度(87.4%;χ2=6.616,P=0.01).结论 18F-FDG PET/CT显像在检测原发性肝癌治疗后AFP升高患者肿瘤复发和(或)转移病灶中有较好的应用价值,但高分化肝细胞癌可能出现假阴性.     

Combined 18F-FDG and 11C-methionine PET scans in patients with newly progressive metastatic prostate cancer.

Metastatic prostate cancer may respond initially to hormone suppression, with involution of tumor sites, but ultimate tumor progression is inevitable. Our aim was to detect the proportion of bone and soft-tissue lesions that represent metabolically active tumor sites in patients with progressive metastatic prostate cancer. METHODS: In a prospective study, we compared 18F-FDG and L-methyl-11C-methionine (11C-methionine) PET with conventional imaging modalities (CIM), which included the combination of 99mTc-methylene diphosphonate scintigraphy, CT, or MRI. Twelve patients with prostate cancer, increasing levels of prostate-specific antigen (PSA), and at least 1 site (index lesion) with new or increasing disease on CIM were studied. The total numbers of soft-tissue and bone-tissue lesions, in a site-by-site comparison, were calculated for all imaging modalities. RESULTS: The sensitivities of 18F-FDG PET and 11C-methionine PET were 48% (167/348 lesions) and 72.1% (251/348 lesions), respectively, with CIM being used as the 100% reference (348/348). 11C-Methionine PET identified significantly more lesions than 18F-FDG PET (P < 0.01). All 12 patients with progressive metastatic prostate cancer had at least 1 lesion site of active metabolism for 18F-FDG or 11C-methionine, which could be used as an index lesion to monitor the metabolic response to therapy. A significant proportion of lesions (26%) had no detectable metabolism of 18F-FDG or 11C-methionine. Although technical factors cannot be totally excluded, we believe that metabolically inactive sites may be necrotic or dormant. More than 95% (251/258) of metabolically active sites (72% of the total number of lesions detected by CIM) metabolize 11C-methionine. 18F-FDG uptake is more variable, with 65% of metabolically active sites (48% of the total number of lesions detected by CIM). CONCLUSION: These findings reflect the different biologic characteristics of the lesions in a heterogeneous tumor such as prostate cancer and suggest that a time-dependent metabolic cascade may occur in advanced prostate cancer, with initial uptake of 11C-methionine in dormant sites followed by increased uptake of 18F-FDG during progression of disease.     

The role of 18F-fluorodeoxyglucose positron emission tomography in gestational trophoblastic tumours: a pilot study

Purpose We conducted a pilot trial to evaluate the value of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) in gestational trophoblastic tumours (GTTs).Methods Patients with placental site trophoblastic tumour (PSTT), high-risk GTT (World Health Organisation score 8, disease onset at postpartum or greater than 6 months after antecedent pregnancy), metastatic GTT, recurrent/resistant GTT after chemotherapy, or post-molar GTT with unexplained abnormal -hCG regression and patients undergoing re-evaluation after salvage treatment were enrolled. PET was undertaken within 1 week after computed tomography (CT). Clinical impacts of additional PET were determined on a scan basis.Results A total of 14 patients were recruited. Sixteen PET scans were performed, with one patient having three serial studies. Benefits of additional PET were seen in 7 of 16 (43.8%) scans; these benefits included disclosure of chemotherapy-resistant lesions (n=2), exclusion of false-positive CT lesions (n=1), detection of an additional lesion not found by conventional imaging (n=1) in high-risk GTT at the start of primary chemotherapy, and confirmation of complete response to treatment for PSTT or to salvage therapy for recurrent/resistant GTT (n=3). On the other hand, in two instances there were false-negative PET findings, six scans yielded no benefit, and one showed an indeterminate lesion.Conclusion Our preliminary results suggest that ¹⁸F-FDG PET is potentially useful in selected patients with GTT by providing precise mapping of metastases and tumour extent upfront, by monitoring treatment response and by localising viable tumours after chemotherapy. A larger study is necessary to further define the role of ¹⁸F-FDG PET in GTT.     

Diagnostic accuracy of 18F-FDG PET in restaging patients with medullary thyroid carcinoma and elevated calcitonin levels.

Medullary thyroid carcinoma (MTC) is a rare endocrine tumor arising from the C-cells of the thyroid gland. Calcitonin is the principal serum tumor marker. A rising calcitonin level after total thyroidectomy for localized disease generally indicates residual, recurrent, or metastatic disease. The role of (18)F-FDG PET in MTC remains somewhat unclear. We reviewed our own experience with (18)F-FDG PET in postthyroidectomy MTC patients with elevated calcitonin. METHODS: From our database, we identified patients with suspected residual, recurrent, or metastatic MTC and elevated calcitonin who had been referred for (18)F-FDG PET between January 2000 and October 2005. (18)F-FDG PET findings were classified as positive or negative on the basis of visual interpretation of the scan. Standardized uptake values (SUVs) were also calculated. The (18)F-FDG PET findings were verified by histopathologic examination, when available, or other imaging studies and clinical follow-up. Any negative (18)F-FDG PET result was considered false-negative. RESULTS: Twenty-eight patients underwent a total of 38 (18)F-FDG PET studies. Calcitonin levels ranged from 106 to 541,000 pg/mL (median, 7,260 pg/mL). There were 23 true-positive, 1 false-positive, and 14 false-negative (18)F-FDG PET scans, yielding an overall sensitivity of 62%. There was no true-positive finding when calcitonin levels were below 509 pg/mL (n = 5). Using an arbitrary cutoff of 1,000 pg/mL, we found that the sensitivity in scans with calcitonin levels greater than 1,000 pg/mL increased to 78% (21/27; 95% confidence interval, 58%-91%). The mean SUV of all lesions with (18)F-FDG uptake was 5.3 +/- 3.2 (range, 2.0-15.9). Among the 14 patients with false-negative (18)F-FDG PET findings, 8 had concurrent anatomic imaging studies and only 2 of these had positive findings. CONCLUSION: (18)F-FDG PET can detect residual, recurrent, or metastatic MTC with a reasonable sensitivity of 78% when the calcitonin level is above 1,000 pg/mL but appears of limited use if the calcitonin level is below 500 pg/mL.     

Complementary roles of 18F-DOPA PET/CT and 18F-FDG PET/CT in medullary thyroid cancer

Serum calcitonin and carcinoembryonic antigen (CEA) are markers of recurrent or persistent disease in medullary thyroid cancer (MTC). However, conventional imaging often fails to localize metastatic disease. Our aim was to compare fluorine-labeled dihydroxyphenylalanine ((18)F-DOPA) and (18)F-FDG PET/CT with multidetector CT (MDCT) and MRI in recurrent or persistent MTC. METHODS: Nineteen MTC patients with increased calcitonin or CEA on follow-up (mean ± SD, 93 ± 91 mo; range, 4-300 mo) after primary therapy were prospectively imaged with 4 techniques: (18)F-DOPA PET/CT, (18)F-FDG PET/CT, MDCT, and MRI. Images were analyzed for pathologic lesions, which were surgically removed when possible. The correlation between the detection rate for each method and the calcitonin and CEA concentrations and histopathologic findings was investigated. Results: On the basis of histology and follow-up, one or more imaging methods accurately localized metastatic disease in 12 (63%) of 19 patients. The corresponding figures for (18)F-DOPA PET/CT, (18)F-FDG PET/CT, MDCT, and MRI were 11 (58%) of 19, 10 (53%) of 19, 9 (47%) of 19, and 10 (59%) of 17, respectively. Calcitonin and CEA correlated with (18)F-DOPA PET/CT (P = 0.0007 and P = 0.0263, respectively) and (18)F-FDG PET/CT findings (both P < 0.0001). In patients with an unstable calcitonin doubling time (n = 8), (18)F-DOPA and (18)F-FDG PET/CT were equally sensitive. In contrast, for patients with an unstable CEA doubling time (n = 4), (18)F-FDG PET/CT was more accurate. CONCLUSION: For most MTC patients with occult disease, (18)F-DOPA PET/CT accurately detects metastases. In patients with an unstable calcitonin level, (18)F-DOPA PET/CT and (18)F-FDG PET/CT are complementary. For patients with an unstable CEA doubling time, (18)F-FDG PET/CT may be more feasible. MRI is sensitive but has the highest rate of false-positive results.     

11C-acetate PET imaging in hepatocellular carcinoma and other liver masses.

It is well known that (18)F-FDG PET has a high average false-negative rate of 40%-50% in the detection of hepatocellular carcinoma (HCC). This is not an acceptable accuracy, particularly in countries where this tumor is prevalent. In this study, we evaluated prospectively the characteristics of (11)C-acetate and (18)F-FDG metabolism in HCC and other liver masses. METHODS: Fifty-seven patients were recruited into this study, with masses consisting of 39 HCC; 3 cholangiocarcinomas; 10 hepatic metastases from lung, breast, colon, and carcinoid primary malignancies; and 5 benign pathologies, including focal nodular hyperplasia (FNH), adenoma, and hemangioma. All patients, except 2 with typical findings of hemangioma and 3 clinically obvious metastases, were confirmed histopathologically by liver biopsy or resection. All patients fasted for at least 6 h and blood glucose concentration was measured before they underwent dual PET radiopharmaceutical evaluation of the upper abdomen with (11)C-acetate and (18)F-FDG. RESULTS: In the subgroup of HCC patients with the number of lesions < or = 3 (32 patients; 55 lesions; mean size +/- SD, 3.5 +/- 1.9 cm), the sensitivity of detection by (11)C-acetate is 87.3% ((11)C-acetate maximum SUV [SUV(max)] = 7.32 +/- 2.02, with a lesion-to-normal liver ratio of 1.96 +/- 0.63), whereas the sensitivity of detection by (18)F-FDG is only 47.3%, and 34% lesions show uptake of both tracers. None of the lesions was negative for both tracers (100% sensitivity using both tracers). In some lesions and in the subgroup of HCC patients (n = 7) with multifocal or diffuse disease, dual-tracer uptake by different parts of the tumor is demonstrated. Histopathologic correlation suggests that the well-differentiated HCC tumors are detected by (11)C-acetate and the poorly differentiated types are detected by (18)F-FDG. All 16 non-HCC malignant (cholangiocarcinoma and metastatic) liver lesions do not show abnormal (11)C-acetate metabolism. Of the benign liver lesions, only FNH shows mildly increased (11)C-acetate activities ((11)C-acetate SUV(max) = 3.59, with a lesion-to-normal liver ratio of 1.25). CONCLUSION: (11)C-Acetate has a high sensitivity and specificity as a radiotracer complementary to (18)F-FDG in PET imaging of HCC and evaluation of other liver masses.     

Increased metabolic activity of indolent liver metastases after resection of a primary colorectal tumor.

In murine models, resection of a primary tumor leads to increased vascularization and accelerated growth of metastases that previously had remained microscopic. To study such a potentially inhibitory effect of primary tumors on the outgrowth of distant metastases in humans, we assessed the metabolic activity of liver metastases by 18F-FDG PET before and after resection of primary colorectal tumors. METHODS: Group A consisted of 8 patients with synchronous colorectal liver metastases who were scheduled for resection of their primary tumor. These patients underwent an (18)F-FDG PET scan shortly before resection and 2-3 wk after resection of the primary tumor. The patients in a control group (group B, n = 9) underwent an 18F-FDG PET scan at the time of diagnosis of the liver metastases and a second scan several weeks later, before initiating treatment. There was no surgical intervention between the two 18F-FDG PET scans in this group. RESULTS: In group A, the maximum and mean standardized uptake values of the liver metastases clearly increased after resection of the primary tumor, by 38% +/- 55% and 42% +/- 52%, respectively, as compared with the first 18F-FDG PET scan. In group B, the maximum and mean standardized uptake values of the second 18F-FDG PET scan were not significantly higher than those of the first 18F-FDG PET scan; -11% +/- 23% and 1% +/- 29%, respectively. The difference in standardized uptake value increase between the 2 groups was statistically significant (P < 0.05). CONCLUSION: Our data cannot differentiate between the immunologic sequels caused by the surgical trauma itself and those caused by removal of the primary tumor. The observation itself, however, of increased metabolic activity after surgical resection of the primary tumor may have direct clinical applications and suggests the administration of antiangiogenic therapy after surgery of the primary tumor.