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.     

18F-FDG PET for posttherapy assessment of Hodgkin's disease and aggressive Non-Hodgkin's lymphoma: a systematic review.

Although studies have shown that (18)F-FDG PET, when used to assess the response of malignant lymphoma after treatment, has a strong ability to predict relapse, its diagnostic accuracy in clinical practice remains unclear. The aim of this study was to systematically review the diagnostic accuracy of (18)F-FDG PET in detecting residual disease at the completion of first-line therapy of Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL). METHODS: We searched relevant articles from 1966 to July 2006 using MEDLINE, EMBASE, SCOPUS, Biological Abstracts, bibliographies, review articles, and textbooks without language restriction. One assessor (for non-English-language studies) or 2 assessors (for English-language studies) independently reviewed each article to abstract relevant study characteristics and results. Relevant individual patient data or subgroup data were provided by the investigators if they were unavailable from the publications. We estimated summary receiver operating characteristic curves and confidence regions for summary sensitivity and specificity. RESULTS: Nineteen studies consisting of 474 HD and 254 aggressive NHL patients were included. These studies had heterogeneity and suboptimal methodologic quality and reporting. Reported ranges for the sensitivity and specificity of (18)F-FDG PET in predicting disease relapse were 0.50-1.00 and 0.67-1.00, respectively, for HD and 0.33-0.77 and 0.82-1.00, respectively, for NHL. These estimates were similar when conventional imaging tests showed a residual mass. For HD studies, the summary receiver operating characteristic curves were similar irrespective of whether a residual mass was detected by conventional tests. Factors explaining the variability of diagnostic estimates were not identified. CONCLUSION: Although currently available evidence is still limited, (18)F-FDG PET seems to have good diagnostic accuracy for assessing residual HD at the completion of first-line treatment. Clinical data on this use of (18)F-FDG PET for aggressive NHL are more limited. Prospective studies with a more rigorous research design, conduct, and reporting would more reliably reveal the clinical diagnostic accuracy of this imaging modality.     

Dual-time-point 18F-FDG PET for the evaluation of gallbladder carcinoma.

Conventional imaging techniques such as ultrasonography, CT, and MRI are able to detect gallbladder abnormalities but are not always able to differentiate a malignancy from other disease processes such as cholecystitis. The purpose of the present study was to evaluate the efficacy of dual-time-point (18)F-FDG PET for differentiating malignant from benign gallbladder disease. METHODS: The study evaluated 32 patients who were suspected of having gallbladder tumors. (18)F-FDG PET (whole body) was performed at 62 +/- 8 min (early) after (18)F-FDG injection and was repeated 146 +/- 14 min (delayed) after injection only in the abdominal region. We evaluated the (18)F-FDG uptake both visually and semiquantitatively. Semiquantitative analysis using the standardized uptake value (SUV) was performed for both early and delayed images (SUV(early) and SUV(delayed), respectively). The retention index (RI) was calculated according to the equation (SUV(delayed) - SUV(early)) x 100/SUV(early). The tumor-to-liver ratio was also calculated. Results: The final diagnosis was gallbladder carcinoma in 23 patients and benign disease in 9 patients. For visual analysis of gallbladder carcinoma, delayed (18)F-FDG PET images improved the specificity of diagnosis in 2 patients. When an SUV(early) of 4.5, SUV(delayed) of 2.9, and RI of -8 were chosen as arbitrary cutoffs for differentiating between malignant and benign conditions, sensitivity increased from 82.6% to 95.7% and 100% for delayed imaging and combined early and delayed imaging (i.e., RI), respectively. With the same criteria, specificity decreased from 55.6% to 44.4% for delayed imaging and combined early and delayed imaging, respectively. The specificity of (18)F-FDG PET improved to 80% in the group with a normal level of C-reactive protein (CRP) and decreased to 0% in the group with an elevated CRP level. For gallbladder carcinoma, both SUV and tumor-to-liver ratios derived from delayed images were significantly higher than the ratios derived from early images (P < 0.0001). CONCLUSION: Delayed (18)F-FDG PET is more helpful than early (18)F-FDG PET for evaluating malignant lesions because of increased lesion uptake and increased lesion-to-background contrast. However, the diagnostic performance of (18)F-FDG PET depends on CRP levels.     

Clinical value of 18F-FDG PET/CT in IgG4-related disease

Annals of Nuclear Medicine - To investigate the clinical value of 18F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in IgG4-related disease (IgG4-RD)....     

18F—FDGPET／CT在鼻咽癌综合治疗后患者随访及预后评估中的价值

鼻咽癌是一类发病率较高、早期发现困难、误诊误治率较高的头颈部恶性肿瘤。多数鼻咽癌患者对放疗敏感,但仍有部分患者出现残留、复发或转移。PET／CT作为现代医学影像重要组成部分之一,将PET的功能显像与CT的解剖成像有机结合,不仅能有效显示肿瘤的增生、代谢、乏氧及细胞的凋亡状态,而且能精确显示肿瘤与其周围脏器组织的解剖结构,在鼻咽癌患者的临床诊断、分期、治疗及预后评估等方面具有重要价值。该文重点就PET／CT对鼻咽癌综合治疗后患者局部残留、复发或转移的诊断价值及预后评估效能进行综述。     

18F-FDG PET/CT在Castleman病中的临床应用价值

目的 评价18F-FDG PET/CT在Castleman病(CD)的临床分型、疗效评价及转化监测中的应用价值.方法 回顾性分析14例CD患者[年龄(45.64±14.30)岁,男、女各7例]的18F-FDGPET/CT影像表现(病灶数量、分布、SUVmax),比较不同临床分型、病理类型、病理转化患者的影像表现,并对4例化疗后复查18 F-FDG PET/CT患者的病灶影像学变化进行记录.数据比较采用Mann-Whitney及Kruskal-Wallis秩和检验.结果 12例病理未发生转化的CD患者,化疗前18 F-FDG PET/CT检查均有1个或多个淋巴结肿大且伴有葡萄糖代谢增高,SUVmax3.94± 1.44(1.9 ～ 6.8);临床类型为单中心(2/12)与多中心(10/12) CD的SUV max分别为4.55±3.18和3.82±1.14,差异无统计学意义(Z=0.22,P＞0.05);病理类型分别为透明血管型(4/12)、浆细胞型(6/12)、混合型(2/12) CD的SUVmax分别为3.56±0.96、4.73± 1.41和2.30±0.57,差异无统计学意义(x2=4.74,P＞0.05).4例(4/12)化疗后复查PET/CT的患者中,3例病灶完全消失,1例病灶缩小、代谢减低.2例(2/14)发生病理转化的患者,SUVmax10.85±2.05,高于未转化者(3.94±1.44;Z=-2.19,P＜0.05).结论 18F-FDGPET/CT对于指导CD的临床分型、评价化疗疗效和监测病理转化均有一定的应用价值.     

Evaluation of 18F-FDG uptake and arterial wall calcifications using 18F-FDG PET/CT.

Glucose metabolic activity expressed as (18)F-FDG uptake may be increased in active atherosclerotic plaque. Calcium depositions are often increased in mature atherosclerotic plaque. The purpose of the present study was to assess the patterns of vascular-wall (18)F-FDG uptake and CT calcifications using combined PET/CT. METHODS: One hundred twenty-two consecutive patients over the age of 50 (47 women and 75 men; mean age, 66 +/- 9 y) undergoing whole-body (18)F-FDG PET/CT for tumor assessment were retrospectively evaluated. PET, CT, and PET/CT slices were generated for review. Abnormal vascular findings in major arteries in the chest and abdomen were categorized as PET positive (PET+), PET negative (PET-), CT positive (CT+), or CT negative (CT-). The topographic relationship between increased vascular-wall (18)F-FDG uptake on PET and the presence of calcifications on CT was assessed on PET/CT fused images, with abnormal sites further classified as PET+/CT+, PET+/CT-, or PET-/CT+. The presence of CT calcifications and increased vascular-wall (18)F-FDG uptake was correlated with age, sex, presence of cardiovascular risk factors, and cardiovascular disease. RESULTS: Abnormal findings were identified at 349 sites. CT calcifications (CT+) were observed at 320 sites (92%) of 100 patients (82%), more commonly in men (P < 0.03), in older patients (P < 0.0001), in patients with hypertension (P < 0.003) or hyperlipidemia (P < 0.04), and in smokers (P < 0.008). Increased vascular-wall (18)F-FDG uptake (PET+) was observed at 52 sites (15%) of 38 patients (31%), more commonly in men (P < 0.02), in older patients (P < 0.0001), and in patients with hypertension (P < 0.02), and was borderline in patients with cardiovascular disease (P = 0.057). PET+ and CT+ findings correlated in 12 patients, a PET+/CT- pattern was found in 18 patients, and 8 patients had increased vascular-wall (18)F-FDG uptake in sites with and without calcifications (PET+/CT+, CT-). Twenty-two patients (18%) had a PET-/CT- pattern. CONCLUSION: Hybrid PET/CT can be used to identify and to correctly localize vascular-wall (18)F-FDG activity. Increased vascular-wall (18)F-FDG activity was found in 15% of sites and CT calcifications were noted in 92% of sites, with congruent findings in 7%. The clinical significance of the relationship between vascular-wall (18)F-FDG uptake and CT calcifications needs to be assessed by further prospective studies with long-term follow up.     

Hodgkin's disease. Prognostic value of Gallium-67 scintigraphy.

AIM: The aim of this study is to assess the clinical impact of gallium-67 scintigraphy, before and after treatment, in patients with Hodgkin's disease, and to compare the overall survival between the patients whose gallium studies after treatment were negative and those whose studies remained positive. METHODS: We have studied 75 patients (40 women, 35 men) with Hodgkin's disease. All the patients underwent (67)Ga scintigraphy at the moment of the diagnosis (basal study) and in the case that basal study was positive (abnormal hyper-uptake focus) we performed follow-up studies after the treatment. We have calculated the overall survival among patients whose studies after treatment were negative (1(st) group) and those whose studies remained positive (2(nd) group) and between patients whose studies were negative at diagnosis (3(rd) group). RESULTS: Gallium scintigraphy was positive at diagnosis in 47 patients (62.6%). In 39 of them we were able to perform the follow-up study after treatment. The follow-up study was negative in 31 patients while in 8 patients the gallium scintigraphy remained positive. The overall survival was significantly higher (p<0.001) in the 1(st) group compared with the 2(nd) group. The overall survival was higher in the 1(st) group compared with the 3(rd) but statistic significance level was not reached. CONCLUSION: Our data suggest that: 1) in Hodgkin's disease (67)Ga scintigraphy is useful to establish the diagnosis of complete remission; 2) if the gallium scan remains positive after treatment, the prognosis of patients is worse than the prognosis of patients with a negative scan.     

Prognostic value of semi-quantitative parameters of 18F-FDG PET/CT in newly diagnosed multiple myeloma patients

Annals of Nuclear Medicine - To investigate the prognostic value of fluroine-18 fluorodexyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) semi-quantitative parameter in...     

颅内肿瘤放射治疗后18F-氟代脱氧葡萄糖PET的临床意义

放射治疗是颅内良恶性肿瘤安全有效的治疗方法,18F—FDG PET可以提供肿瘤细胞生物特性信息,能区分颅内肿瘤放射治疗后射线损伤与肿瘤复发,灵敏度为80%-90％,特异度为 40%～100％;能预测3～4级复发恶性胶质瘤放射治疗的生存时间,预测颅内肿瘤放射治疗预后和评价治疗反应;结合其他影像方法可提高颅内肿瘤放射治疗诊断准确性。     

18F-FDG PET显像诊断肾上腺肿瘤

目的　评价1 8F 脱氧葡萄糖 (FDG)PET显像对肾上腺肿瘤的诊断价值。方法　对 2 1例肾上腺肿瘤患者共 2 2个肾上腺病灶行1 8F FDGPET显像 ,对显像结果进行定性和半定量分析 ,并与CT和 (或 )MRI、针刺活组织检查、术后病理检查结果进行对比研究。结果　 9例肾上腺病灶处无明显FDG浓集 ,PET显像诊断为良性病变 ;12例病灶处FDG明显浓集 ,诊断为恶性病变。与病理检查结果比较 ,PET显像定性准确性为 10 0 % ,CT和 (或 )MRI为 6 4 %。良性病变与周围正常组织 (T N)放射性比值为 0 3～ 1 3,平均为 0 7,标准摄取值 (SUV)为 0 98～ 3 89,平均为 1 89;恶性病变T N比值为 3 1～15 1,平均为 6 9,SUV为 3 10～ 15 5 2 ,平均为 6 4 1,两组间差异均有显著性 (P均 <0 0 0 1)。病变性质与肿块大小无相关性。其中 4例PET显像发现了CT和 (或 )MRI未发现的局部淋巴结和远处转移灶12处。结论　1 8F FDGPET显像对肾上腺肿瘤定性诊断的准确性明显高于CT和 (或 )MRI。     

18F-FDG PET/CT in the evaluation of adrenal masses.

Our purpose was to evaluate the performance of (18)F-FDG PET/CT, using data from both the PET and the unenhanced CT portions of the study, in characterizing adrenal masses in oncology patients. METHODS: One hundred seventy-five adrenal masses in 150 patients referred for (18)F-FDG PET/CT were assessed. Final diagnosis was based on histology (n = 6), imaging follow-up (n = 118) of 6-29 mo (mean, 14 mo), or morphologic imaging criteria (n = 51). Each adrenal mass was characterized by its size; its attenuation on CT, expressed by Hounsfield units (HU); and the intensity of (18)F-FDG uptake, expressed as standardized uptake value (SUV). Receiver operating characteristic curves were drawn to determine the optimal cutoff values of HU and SUV that would best discriminate between benign and malignant masses. RESULTS: When malignant lesions were compared with adenomas, PET data alone using an SUV cutoff of 3.1 yielded a sensitivity, specificity, positive predictive value, and negative predictive value of 98.5%, 92%, 89.3%, 98.9%, respectively. For combined PET/CT data, the sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 98%, 97%, 100%, respectively. Specificity was significantly higher for PET/CT (P < 0.01). Fifty-one of the 175 masses were 1.5 cm or less in diameter. When a cutoff SUV of 3.1 was used for this group, (18)F-FDG PET/CT correctly classified all lesions. CONCLUSION: (18)F-FDG PET/CT improves the performance of (18)F-FDG PET alone in discriminating benign from malignant adrenal lesions in oncology patients.     

18F-FDG显像对淋巴瘤分期及疗效评价的价值

目的探讨18F-脱氧葡萄糖(FDG)PET和PET/CT显像在淋巴瘤诊断、分期及疗效评价中的价值.方法 107例淋巴瘤或淋巴瘤疑似患者行18F-FDG PET或PET/CT显像,其中16例多次行PET或PET/CT显像.所有患者皆经病理学检查确诊,随访时间>6个月.结果淋巴瘤31例,PET显像阳性30例(96.8%),7例淋巴结转移癌及活动性淋巴结结核PET显像均为阳性,淋巴瘤与原发灶不明的淋巴结转移癌及活动性淋巴结结核难以鉴别.37%(10/27例)初诊淋巴瘤PET显像多发现恶性病灶而提高临床分期.16例淋巴瘤行多次PET显像,发现8例治疗后病灶消失,2例缓解,1例肿瘤复发,5例无瘤生存,皆与临床相符.53例淋巴瘤治疗后行PET显像,其中8例临床确认有肿瘤复发或明显残余,PET显像均为阳性;45例临床疗效为完全缓解(CR)和部分缓解(PR)的患者中,PET显像阳性者18例,3例肿瘤处于活跃状态,15例(非霍奇金淋巴瘤12例,霍奇金淋巴瘤3例)处于抑制状态,PET显像后改变了进一步临床治疗方案.结论 18F-FDG PET显像对检测淋巴瘤的体内分布及分期灵敏、准确、全面,但难以与活动性淋巴结结核、原发灶不明的淋巴结转移癌相鉴别.18F-FDG PET显像能灵敏、准确地检出淋巴瘤复发及残余病灶,对疗效评价及指导临床治疗有重要价值.     

Dual time point 18F-FDG PET for the evaluation of pulmonary nodules.

18F-FDG PET has reached widespread application in the assessment of pulmonary nodules. This study compares the diagnostic accuracy of standard 18F-FDG PET scanning with those of dual time point 18F-FDG PET scanning. METHODS: Thirty-six patients (21 women, 15 men; mean age, 67 y; range, 36-88 y) with 38 known or suspected malignant pulmonary nodules underwent PET of the thorax at 2 time points: scan 1 at 70 min (range, 56-110 min) and scan 2 at 123 min (range, 100-163 min) after the intravenous injection of 2.5 MBq 18F-FDG per kilogram of body weight. All scanning was performed on a dedicated C-PET scanner. The mean interval between the scans was 56 min (range, 49-64 min). Regions of interest were overlaid onto each fully corrected image in the areas of the radiographically known lung densities. The standardized uptake values (SUVs) were calculated for both time points. RESULTS: Surgical pathology and follow-up revealed 19 patients with 20 malignant tumors, whereas 16 patients had benign lesions. The tumor SUVs (mean +/- SD) were 3.66 +/- 1.95 (scan 1) and 4.43 +/- 2.43 (scan 2) (20.5% +/- 8.1% increase; P < 0.01). Four of 20 malignant tumors had SUVs of <2.5 on scan 1 (range, 1.12-1.69). Benign lesions had SUVs of 1.14 +/- 0.64 (scan 1) and 1.11 +/- 0.70 (scan 2) (P = not significant). Standard PET scanning (single time point) with a threshold SUV of 2.5 (at time point 1) reached a sensitivity of 80% and a specificity of 94%; dual time point scanning with a threshold value of 10% increase between scan 1 and scan 2 reached a sensitivity of 100% with a specificity of 89%. CONCLUSION: Dual time point 18F-FDG PET results in a very high sensitivity and specificity for detection of malignant lung tumors.     

18F-FDG与18F-FLT PET/CT延迟显像对肺结节诊断效能的评价

目的 通过对多中心、前瞻性研究中接受了18F-脱氧葡萄糖(FDG)与18F-脱氧胸腺嘧啶核苷(FLT)延迟显像病例的分析,探讨18F-FDG与18F-FLT延迟显像对肺结节诊断的效能.方法 6个PET/CT中心,从2006年1月至2007年6月,按照统一标准,采用同机型、同一扫描条件,开展了肺结节样病变18F-FLT和18F-FDG PET/CT显像的多中心临床研究.在经确诊的55例病例中,25例患者进行了18F-FLT显像和延迟显像,34例患者进行了18F-FDG延迟显像.按常规计算延迟显像时病灶最大标准摄取值(SUVmax)及与早期显像时SUVmax相比的变化率(△SUVmax).对照临床确诊结果分析其诊断效能.采用SPSS11.0软件进行统计学处理.结果 18F-FDG延迟显像患者中,6例肺癌中5例、12例结核中9例、16例炎症或其他良性结节中9例的SUVmax较早期相升高.18F-FLT延迟显像组中,7例肺癌中3例、8例结核中3例和10例其他良性病灶中2例的SUVmax上升.经分组统计分析,不同疾病组间18F-FDG延迟显像SUVmax和△SUVmax差异无统计学意义;18F-FLT延迟显像SUVmax和△SUVmax组间差异也无统计学意义.无论18F-FDG还是18F-FLT,延迟显像的诊断效能均不如早期相.无论早期还是延迟显像,单独18F-FDG或18F-FLT显像的诊断效能均不如二者联合应用.结论 18F-FDG和18F-FLT延迟显像的SUVmax变化规律性不强,不宜单独应用于肺结节的鉴别诊断.     

Increased 18F-FDG uptake in degenerative disease of the spine: Characterization with 18F-FDG PET/CT.

We determined the prevalence of abnormal spinal 18F-FDG uptake and assessed the relationship between the severity of findings on 18F-FDG PET and the severity of degenerative spinal disease (DSD) on CT. METHODS: PET/CT scans of 150 patients >18 y old, referred for whole-body 18F-FDG PET/CT for evaluation of known or suspected malignancy from June to July 2002, were analyzed retrospectively for the presence of increased 18F-FDG uptake in the spine and for anatomic correlates. Initially, PET images were examined and foci of 18F-FDG uptake in the spine were graded on a 0-4 scale based on intensity of 18F-FDG uptake (0 = definitely normal, 1 = probably normal, 2 = equivocal, 3 = probably abnormal, 4 = definitely abnormal). From PET alone, an impression as to whether lesions were most likely metastases or degenerative, as well the level of the spine involved, was also recorded. CT images of all 150 patients were reviewed independently by a musculoskeletal radiologist, who was unaware of patient identification, history, and findings of other imaging modalities, with the location recorded and severity graded on a 4-point-scale (0 = normal, 1 = mild, 2 = moderate, 3 = severe for both degenerative disk and facet disease). The relationship between PET and CT findings was then determined. RESULTS: Of the 150 patients, 63 (42.0%) had no abnormal findings in the spine on PET (grade 0), 27 (18.0%) had grade 1, 25 (16.7%) had grade 2, 17 (11.3%) had grade 3, and 16 patients (10.7%) had grade 4 18F-FDG uptake for DSD. Two additional patients had apparent spinal metastases with no degenerative changes. Five patients had metastases and DSD (included above). Of the patients who had abnormal spinal findings graded as probable or definite for DSD on CT (grades 3-4), 11 had abnormal findings in the cervical spine, 16 in the thoracic spine, and 23 patients in the lumbosacral spine. Seven patients (4.7%) had PET findings suggestive of spinal metastases. For patients with a maximum regional DSD score of 3, the mean 18F-FDG uptake for that spinal level was 1.4 +/- 1.5, whereas for patients with a maximum regional DSD score of 0, the mean PET grade was significantly lower at 0.4 +/- 0.9 (P = 0.0001). CONCLUSION: Incidental findings on PET suggestive of DSD are common (22% of patients), most common in the lumbosacral spine, and can be recognized on CT. The severity of PET findings correlates with the severity of degenerative disk and facet disease as graded by CT, likely due to the fact that the inflammatory process that accompanies DSD is evident on PET. Increased 18F-FDG uptake in DSD should not be confused with metastatic disease.     

Prognostic value of metabolic tumor burden on 18F-FDG PET in nonsurgical patients with non-small cell lung cancer

Purpose

The objective of this study was to assess the prognostic value of metabolic tumor burden on 2-deoxy-2-[¹⁸F]fluoro-D-glucose (¹⁸F-FDG) positron emission tomography (PET)/CT measured with metabolic tumor volume (MTV) and total lesion glycolysis (TLG), independent of Union Internationale Contra la Cancrum (UICC)/American Joint Committee on Cancer (AJCC) tumor, node, and metastasis (TNM) stage, in comparison with that of standardized uptake value (SUV) in nonsurgical patients with non-small cell lung cancer (NSCLC).

Methods

This study retrospectively reviewed 169 consecutive nonsurgical patients (78 men, 91 women, median age of 68?years) with newly diagnosed NSCLC who had pretreatment ¹⁸F-FDG PET/CT scans. The ¹⁸F-FDG PET/CT scans were performed in accordance with National Cancer Institute guidelines. The MTV of whole-body tumor (MTV_WB), of primary tumor (MTV_T), of nodal metastases (MTV_N), and of distant metastases (MTV_M); the TLG of whole-body tumor (TLG_WB), of primary tumor (TLG_T), of nodal metastases (TLG_N), and of distant metastases (TLG_M); the SUV_max of whole-body tumor (SUV_maxWB), of primary tumor (SUV_maxT), of nodal metastases (SUV_maxN), and of distant metastases (SUV_maxM) as well as the SUV_mean of whole-body tumor (SUV_meanWB), of primary tumor (SUV_meanT), of nodal metastases (SUV_meanN), and of distant metastases (SUV_meanM) were measured with the PETedge tool on a MIMvista workstation with manual adjustment. The median follow-up among survivors was 35?months from the PET/CT (range 2?C82?months). Statistical methods included Kaplan-Meier curves, Cox regression, and C-statistics.

Results

There were a total of 139 deaths during follow-up. Median overall survival (OS) was 10.9?months [95% confidence interval (CI) 9.0?C13.2?months]. The MTV was statistically associated with OS. The hazard ratios (HR) for 1 unit increase of ln(MTV_WB), ??(MTV_T), ??(MTV_N), and ??(MTV_M) before/after adjusting for stage were: 1.47/1.43 (p?p?p?p?=?0.007/0.043), respectively. TLG had statistically significant associations with OS with the HRs for 1 unit increase in ln(TLG_WB), ??(TLG_T), ??(TLG_N), and ??(TLG_M) before/after adjusting for stage being 1.36/1.33 (p?p?=?0.001/0.002), 1.05/1.04 (p?p?=?0.003/0.024), respectively. The ln(SUV_maxWB) and ??(SUV_maxN) were statistically associated with OS with the corresponding HRs for a 1 unit increase before/after adjusting for stage being 1.46/1.43 (p?=?0.013/0.024) and 1.22/1.16 (p?=?0.002/0.040). The ??(SUV_meanN) was statistically associated with OS before and after adjusting for stage with HRs for a 1 unit increase of 1.32 (p?p?=?0.015), respectively. The ??(SUV_meanM) and ??(SUV_maxM) were statistically associated with OS before adjusting for stage with HRs for a 1 unit increase of 1.26 (p?=?0.017) and 1.18 (p?=?0.007), respectively, but not after adjusting for stage (p?=?0.127 and 0.056). There was no statistically significant association between OS and ??(SUV_maxT), ln(SUV_meanWB), or ??(SUV_meanT). There was low interobserver variability among three radiologists with intraclass correlation coefficients (ICC) greater than 0.94 for SUV_maxWB, ln(MTV_WB), and ln(TLG_WB). Interobserver variability was higher for SUV_meanWB with an ICC of 0.806.

Conclusion

Baseline metabolic tumor burdens at the level of whole-body tumor, primary tumor, nodal metastasis, and distant metastasis as measured with MTV and TLG on FDG PET are prognostic measures independent of clinical stage with low inter-observer variability and may be used to further stratify nonsurgical patients with NSCLC. This study also suggests MTV and TLG are better prognostic measures than SUV_max and SUV_mean. These results will need to be validated in larger cohorts in a prospective study.