The Impact of 18-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography on the Staging and Management of Primary Rectal Cancer

Purpose  18-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) has a role in recurrent colorectal cancer. This study was designed to assess the impact of PET-CT on management of primary rectal cancer. Methods  Eighty-three patients with rectal cancer underwent PET-CT scan between 2002 and 2005. Referring physicians prospectively recorded stage and management plan after conventional imaging before PET-CT scan, which were compared to subsequent stage and management after PET-CT. Results  Staging PET-CT caused a change in stage from conventional imaging in 26 patients (31 percent). Twelve (14 percent) were upstaged (7 change in N stage; 4 change in M stage; 1 change in N and M stage), and 14 (17 percent) were downstaged (10 change in N stage; 3 change in M stage; 1 change in N and M stage). PET-CT scan altered management intent in seven patients (8 percent) (curative to palliative 6 patients; palliative to curative 1 patient). Management was altered in ten patients (12 percent). There was no difference in impact with respect to tumor height. Conclusions  PET-CT scan impacts the management of patients with primary rectal cancer and influences staging/therapy in a third of patients and should be a component of rectal cancer workup. Read at the meeting of The American Society of Colon and Rectal Surgeons, St Louis, Missouri, June 2 to 6, 2007.     

Positron Emission Tomography's Utility in Esophageal Cancer Management

Esophageal cancer is rising in incidence and has a poor prognosis. Positron Emission Tomography (PET) is increasingly being investigated as a tool to more discriminately manage these patients. Several studies have indicated benefits in the use of PET for staging and assessment of treatment response while others have provided contradicting results. There are many possible factors that might contribute to these results, including variability in the manner of PET administration and interpretation, timing, and study design. PET acquired after chemoradiation or chemotherapy may give important prognostic information that can guide additional management decisions. Studies have had substantial variability in the timing and manner of assessing PET for this purpose, and additional study is needed.     

统计参数图软件对Alzheimer病患者脑PET图像的初步分析

目的 探讨阿尔茨海默病(AD)患者脑葡萄糖代谢特点及正电子发射计算机断层扫描(PET)对AD的诊断价值。方法 应用统计参数图(SPM)软件对13例AD患者和13例年龄、性别和文化程度相匹配的健康对照者脑PET检查结果进行处理分析。结果 (1)健康老年人可出现顶叶葡萄糖代谢的减低，但程度较轻；AD组全脑葡萄糖代谢减低，以顶叶为最明显，其次为颞叶，再次为额叶；(2)AD组扣带回31、23、7、30区，顶枕40、39区，颞叶20区和额叶9、6、8区等部位葡萄糖代谢减退较明显，差异有显著性(P＜0．05、0．001)。降低区域双侧基本对称，但额叶和颞叶的降低区左侧明显大于右侧。结论 AD患者脑葡萄糖代谢普遍性降低，个别脑区较为明显。扣带回的31、23、7、30区，顶枕的40、39区，颞叶的20区和额叶的9、6、8区等部位的葡萄糖代谢半定量指标降低可作为诊断AD的重要依据之一。     

Utility of 2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography in Managing Patients of Colorectal Cancer With Unexplained Carcinoembryonic Antigen Elevation at Different Levels

PURPOSE Serum carcinoembryonic antigen elevation without detectable relapse during colorectal cancer follow-up presents a challenge. This study was designed to evaluate the utility of fluorine-18-labeled 2-fluoro-2-deoxy-D-glucose positron emission tomography in colorectal cancer patients with unexplained carcinoembryonic antigen elevation at different levels. METHODS Thirty-seven colorectal cancer patients referred for positron emission tomography after primary surgery who had serum carcinoembryonic antigen levels >5 ng/ml and negative or equivocal conventional imaging studies were analyzed. Patient status was determined by histopathology and/or clinical follow-up. Grouping as disease-free, potentially resectable, or advanced disease was performed. The management impact was defined as the percentage of patients with a true-positive positron emission tomography result. RESULTS The sensitivity, specificity, and accuracy of positron emission tomography for relapse detection were 89, 89, and 89 percent, respectively. The management impact was 68 percent. In 24 patients with carcinoembryonic antigen levels <25 ng/ml, positron emission tomography helped correct patient grouping in 20 patients (83 percent), including 8 in the disease-free group, 5 in the potentially resectable group, and 7 in the advanced-disease group. In 13 patients with carcinoembryonic antigen levels >25 ng/ml, positron emission tomography identified 8 patients in the advanced-disease group and 1 patient in the potentially resectable group but missed 2 patients with relapse and undergrouped 2 patients in the advanced-disease group as potentially resectable. CONCLUSIONS 2-fluoro-2-deoxy-D-glucose positron emission tomography can help triage patients for appropriate management with unexplained carcinoembryonic antigen elevation <25 ng/ml. For patients with unexplained elevation of carcinoembryonic antigen >25 ng/ml, the utility of positron emission tomography is mainly to confirm the presence of advanced disease and occasionally to identify potentially resectable lesions. Supported by grants from the National Science Council - Taiwan (NSC 93-2314-B-182A-008).     

Preoperative Radiation Response Evaluated by 18-Fluorodeoxyglucose Positron Emission Tomography Predicts Survival in Locally Advanced Rectal Cancer

Purpose  This study focuses on the prognostic survival value of postirradiation metabolic activity in primary rectal cancer as measured with 18-fluorodeoxyglucose positron emission tomography. Methods  From July 1995 to March 2002, all 59 patients underwent two series of fluorodeoxyglucose positron emission tomography: one before preoperative radiation (standardized uptake values-1), and the other two to three weeks after radiation (standardized uptake values-2). Standardized uptake values-1 and standardized uptake values-2 correspond to before and after radiation, respectively. Results  In univariate analysis, the following emerged as significant prognostic variables: with or without residual tumor, pathologic differentiation, with or without recurrence, standardized uptake values-2, and with or without lymph node metastases. In multivariate analysis, residual tumor and standardized uptake values-2 were significant prognostic factors for survival. The median survival and the five-year overall survival rate comparing standardized uptake values-2 values <5 vs. >5 were 95 vs. 42 months and 70 vs. 44 percent, respectively (P = 0.042). Conclusion  A significant survival benefit was observed in patients with low fluorodeoxyglucose uptake after preoperative radiotherapy in primary tumors of rectal cancer.     

Positron Emission Tomography Scan Reveals an Unusual Source for Cervical Lymphadenopathy: Right Colon Cancer

Cervical lymphadenopathy is usually related to the presence of an inflammatory disease or to a malignant localization. In the event of metastatic findings, the thyroid gland is the most likely primary site of a tumor. Metastatic lymphadenopathy represents a challenge when the primary tumor is unknown. A 64-year-old female with a supraclavicular palpable mass in the absence of underlying thyroid disease underwent ultrasonography of the neck, biopsy of the pathological lymph node, fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) and colonoscopy until right colon cancer was diagnosed. FDG-PET is a fast and reliable tool to discover the primary site of cervical masses of unknown origin.     

PET显像评价心肌激光血运重建术的临床价值

对１１例心肌激光血运重建术的冠心病率要术前,术后６个月和１２个月进行正电子发射断层扫描心肌灌注和代谢显像分析。     

正电子发射断层扫描显像评价存活心肌的应用现状

随着冠状动脉血运重建术的广泛应用,如何选择适应证以及术后疗效的判断日益引起人们的高度重视,因此,存活心肌的检测,区分心肌损害的可逆性(冬眠心肌、顿抑心肌)和不可逆性(瘢痕组织),对冠状动脉的血运重建术具有决策和预后判断价值.目前,正电子发射断层扫描(PET)被认为是一种评价冠心病患者心肌存活独特、无创而敏感的方法.通过回顾近年来PET显像评价存活心肌的各种方法及对照研究,概述PET对估价存活心肌的价值和最新进展,并对其未来进行初步展望.     

正电子显像在心血管疾病中的研究现状和进展

正电子发射体层摄影术是一种无创性的探测生理性放射性核素在机体内分布的断层显像技术。正电子发射体层摄影术显像不仅广泛应用于肿瘤、神经精神系统等疾病的科学研究和临床工作,同时该技术也广泛应用于对各种心脏疾病的科学研究和临床实践中,如冠心病的诊断、冠心病严重程度的判断、存活心肌的检测、微血管疾病的评价和心脏交感神经功能的研究等。     

Tumor Hypoxia Detected by Positron Emission Tomography with <Superscript>60</Superscript>Cu-ATSM as a Predictor of Response and Survival in Patients Undergoing Neoadjuvant Chemoradiotherapy for Rectal Carcinoma: A Pilot Study

PURPOSE  The response of rectal cancers to neoadjuvant chemoradiotherapy is variable. Tumor hypoxia reduces the effectiveness of both radiation therapy and chemotherapy and is a well-known risk factor for tumor radioresistence. We hypothesized that imaging with the novel hypoxia-detecting agent, ⁶⁰Cu-diacetyl-bis (N⁴-methylthiosemicarbazone) (⁶⁰Cu-ATSM), previously validated in cervical and lung cancers, would predict the response of rectal cancers to neoadjuvant chemoradiotherapy and prognosis. METHODS  Patients with locally invasive (T2–4) primary or node-positive rectal cancer located <12 cm from the anal verge were recruited for this pilot study. Pretreatment tumor size and stage were determined by endorectal ultrasonography, CT, and magnetic resonance imaging. Eleven patients also underwent clinical positron emission tomography with ¹⁸F-fluorodeoxyglucose at the discretion of the treating clinician. The primary tumor was imaged by positron emission tomography with ⁶⁰Cu-ATSM, and accumulation of the tracer was measured semiquantitatively by determining the tumor-to-muscle activity ratio. Neoadjuvant chemoradiotherapy was then administered (within 2 weeks of ⁶⁰Cu-ATSM-positron emission tomography) and consisted of 45 Gy given in 25 fractions to the pelvis with continuous intravenous infusion of 5-fluorouracil (225 mg/m²/day). Proctectomy was performed six to eight weeks after neoadjuvant chemoradiotherapy and the tumor submitted to pathology for size measurement and staging. Tumor-to-muscle activity ratios were compared with tumor ¹⁸F-fluorodeoxyglucose uptake, tumor response to neoadjuvant chemoradiotherapy, and with patient survival. RESULTS  Nineteen patients were enrolled in the study, two of whom were excluded from final analysis (1 death during neoadjuvant chemoradiotherapy and 1 tumor perforation during neoadjuvant chemoradiotherapy requiring emergent surgery). Of the 17 remaining patients, 14 had a reduction in tumor size and 13 were downstaged. The median tumor-to-muscle activity ratio of 2.6 discriminated those with worse prognosis from those with better prognosis. Both overall and progression-free survivals were worse with hypoxic tumors (tumor-to-muscle activity ratio >2.6) than with nonhypoxic tumors (tumor-to-muscle activity ratio ≤2.6; both P < 0.05). In addition, 2 of the 3 tumors with no change in size had tumor-to-muscle activity ratios >2.6 (positive predictive value 66 percent), whereas 6 of 14 with decreased size had tumor-to-muscle activity ratios >2.6 (negative predictive value 57 percent). Three of the 4 tumors not downstaged had tumor-to-muscle activity ratios >2.6 (positive predictive value 75 percent), whereas 5 of 13 downstaged tumors had tumor-to-muscle activity ratios >2.6 (negative predictive value 62 percent). The mean tumor-to-muscle activity ratio for downstaged tumors (2.2) was significantly lower than that of nondownstaged tumors (3.3) (P = 0.03). The difference in mean tumor-to-muscle activity ratio between downsized (2.3) and nondownsized (2.9) tumors did not reach statistical significance (P = 0.36). Tumor ¹⁸F-fluorodeoxyglucose uptake (n = 11) did not correlate with ⁶⁰Cu-ATSM uptake (r = 0.4; P = 0.9) and there was no significant difference in mean tumor ¹⁸F-fluorodeoxyglucose uptake between patients with hypoxic tumors and those with normoxic tumors (P = 0.3). CONCLUSIONS  The results of this small pilot study suggest that ⁶⁰Cu-ATSM-PET may be predictive of survival and, possibly, tumor response to neoadjuvant chemoradiotherapy in patients with rectal cancer. A larger Phase II study is warranted to validate these results. Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, St. Louis, Missouri, June 2 to 6, 2007. Supported by an American Cancer Society Institutional Research Grant (ACS-IRG #58–010–46).     

Correlation of GLUT-1 Overexpression, Tumor Size, and Depth of Invasion with 18F-2-fluoro-2-deoxy-d-glucose Uptake by Positron Emission Tomography in Colorectal Cancer

We investigated the wide variability of 18F-2-fluoro-2-deoxy-d-glucose (FDG) uptake, semiquantified as standardized uptake value (SUV), in positron emission tomography (PET) scanning, in 20 patients with colorectal cancer (CRC), including 1 with synchronous hepatic metastasis. The sensitivity of PET in CRC diagnosis was 100%, with a mean SUV of 8.0 (3.1–11.9). Tumor size and depth of invasion were associated with higher SUVs (P=.0004, .042, respectively). Strong glucose transporter-1 (GLUT-1) expression had significantly positive correlation with the SUV (r=.619, P=.003). GLUT-1 expression revealed positive staining in 17 (85%) of the 20 primary lesions. The central part of the tumor, thought to be relatively hypoxic, had stronger GLUT-1 expression and a higher SUV than the periphery, in both the primary tumor and hepatic metastatic foci. Our data suggest that the SUVs of FDG uptake in PET may be a noninvasive biomarker for advanced CRC, indicative of a large hypoxic tumor with deep invasion.     

Positron emission tomography/computed tomography improves diagnostics of inflammatory arteritis

Based on the unique property of fluorine-18 fluorodeoxyglucose, localization and follow-up of hypermetabolic processes is possible with positron emission tomography (PET). The dual-modality PET/computed tomography (CT) systems provide intrinsically fused morphologic and functional data in a single examination. We report on two patients with inflammatory aortitis and positive PET/CT findings. A 57-year-old woman with an inflammatory process involving the thoracolumbal aorta with an aneurysm and a 48-year-old woman with an aneurysm of the thoracic aorta and pronounced fluorodeoxyglucose-uptake. The advantages in differentiation of vessel wall structures compared with PET or CT alone are pointed out.     

Positron Emission Tomography in the Study of Hepatic Encephalopathy

Positron emission tomography (PET) is a powerful and versatile tool for the investigation of hepatic encephalopathy (HE). This nuclear medicine imaging technique produces quantitative images of the distribution of a radiopharmaceutical at one or more times after its administration. Thus, PET images can be used as data in mathematical models of physiologically important processes, including cerebral blood flow, an index of neural activity, or glucose and ammonia metabolism. Using PET, we have demonstrated abnormalities in all of these processes in patients, even though many had only minimal HE. In HE patients we have found increases in the cerebral ammonia metabolic rate, because of hyperammonemia and an increase in the permeability of the blood–brain barrier to ammonia and abnormal patterns of blood flow and glucose metabolism. In a recent collaborative study, alterations in the resting glucose metabolic rate were found to have significant correlations with a variety of neuropsychological tests used to detect mild HE including Trailmaking A and B, symbol-digit, and other tests. Activation techniques have not yet been applied to map sites affected by HE, but recent data using the paced serial auditory addition test and an auditory continuous performance task have proven to be sensitive indicators in minimally impaired patients. The full potential of PET to evaluate neurotransmitter function is as yet unrealized.     

正电子发射计算机断层显像计算机断层扫描在系统性血管炎诊断及病情评估中的应用

系统性血管炎临床表现复杂,对于缺乏特征性表现者的诊断和病情严重程度评估,临床医生面临巨大的挑战。现有影像学检查手段对系统性血管炎的早期、活动性病变敏感性较低。正电子发射计算机断层显像与计算机断层扫描技术(positron emission tomographycomputed tomography,PETCT)对系统性血管炎中巨细胞动脉炎风湿性多肌痛、大动脉炎等大血管炎的诊断具有比较高的敏感新和特异性,特别是在疾病的早期和活动期,而对于中小血管受累的系统性血管炎并无太大帮助。通过PETCT可以全面了解系统性血管炎的解剖和功能定位,弥补其他影像学检查的不足。应注意在PETCT上系统性血管炎与其他血管疾病的鉴别。PETCT检查在系统性血管炎疗效评估中的作用尚有待进一步研究。     

Diagnostic accuracy of fluorine-18-fluorodeoxyglucose positron emission tomography in gallbladder cancer: A meta-analysis

AIM: To meta-analyze published data about the diagnostic accuracy of fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and PET/computed tomography (PET/CT) in the evaluation of primary tumor in patients with gallbladder cancer (GBCa).METHODS: A comprehensive literature search of studies published through 30^th June 2014 regarding the role of ¹⁸F-FDG PET and PET/CT in the evaluation of primary gallbladder cancer (GBCa) was performed. All retrieved studies were reviewed. Pooled sensitivity and specificity of ¹⁸F-FDG PET or PET/CT in the evaluation of primary GBCa were calculated. The area under the summary receiving operator characteristics curve (AUC) was calculated to measure the accuracy of these methods. Sub-analyses considering the device used (PET vs PET/CT) were carried out.RESULTS: Twenty-one studies comprising 495 patients who underwent ¹⁸F-FDG PET or PET/CT for suspicious GBCa were selected for the systematic review. The meta-analysis of 13 selected studies provided the following results: sensitivity 87% (95%CI: 82%-92%), specificity 78% (95%CI: 68%-86%). The AUC was 0.88. Improvement of sensitivity and specificity was observed when PET/CT was used.CONCLUSION: ¹⁸F-FDG-PET and PET/CT demonstrated to be useful diagnostic imaging methods in the assessment of primary tumor in GBCa patients, nevertheless possible sources of false-negative and false-positive results should be kept in mind. PET/CT seems to have a better diagnostic accuracy than PET alone in this setting.