Value of 18-Fluorodeoxyglucose Positron Emission Tomography in the Management of Patients With Cystic Tumors of the Pancreas

OBJECTIVE: To assess the reliability of 18-fluorodeoxyglucose positron emission tomography (18-FDG PET) in distinguishing benign from malignant cystic lesions of the pancreas. SUMMARY BACKGROUND DATA: The preoperative differential diagnosis of cystic lesions of the pancreas remains difficult: the most important point is to identify malignant or premalignant cysts that require resection. 18-FDG PET is a new imaging procedure based on the increased glucose metabolism by tumor cells and has been proposed for the diagnosis and staging of pancreatic cancer. METHODS: During a 4-year period, 56 patients with a suspected cystic tumor of the pancreas underwent 18-FDG PET in addition to computed tomography scanning, serum CA 19-9 assay, and in some instances magnetic resonance imaging or endoscopic retrograde cholangiopancreatography. The 18-FDG PET was analyzed visually and semiquantitatively using the standard uptake value. The accuracy of 18-FDG PET and computed tomography was determined for preoperative diagnosis of a malignant cyst. RESULTS: Seventeen patients had malignant tumors. Sixteen patients (94%) showed 18-FDG uptake with a standard uptake value of 2.6 to 12.0. Twelve patients (70%) were correctly identified as having malignancy by computed tomography, CA 19-9 assay, or both. Thirty-nine patients had benign tumors: only one mucinous cystadenoma showed increased 18-FDG uptake (standard uptake value 2.6). Five patients with benign cysts showed computed tomography findings of malignancy. Sensitivity, specificity, and positive and negative predictive values for 18-FDG PET and computed tomography scanning in detecting malignant tumors were 94%, 97%, 94%, and 97% and 65%, 87%, 69%, and 85%, respectively. CONCLUSIONS: 18-FDG PET is more accurate than computed tomography in identifying malignant pancreatic cystic lesions and should be used, in combination with computed tomography and tumor markers assay, in the preoperative evaluation of patients with pancreatic cystic lesions. A positive result on 18-FDG PET strongly suggests malignancy and, therefore, a need for resection; a negative result shows a benign tumor that may be treated with limited resection or, in selected high-risk patients, with biopsy, follow-up, or both.     

Clinical usefulness of 18-fluorodeoxyglucose positron emission tomography in the management of patients with nonpancreatic periampullary neoplasms

BACKGROUND: 18-Fluorodeoxyglucose positron emission tomography (18-FDG PET) has been investigated for the diagnosis and staging of gastrointestinal malignancies including pancreatic adenocarcinoma. The aim of this study was to examine the clinical usefulness of 18-FDG PET in the diagnosis and follow-up evaluation of patients with periampullary neoplasms. METHODS: Twenty-five patients underwent whole-body 18-FDG PET and abdominal computed tomography (CT). Pathologic confirmation was obtained in all patients by surgical resection or biopsy examination. The 18-FDG PET was analyzed visually and semiquantitatively using the standard uptake value (SUV). Positivity was assumed when a focal uptake occurred with an SUV of 2.5 or greater. RESULTS: Between January 1998 and December 2003, 14 ampullary, 7 bile duct, and 4 duodenal tumors were included in the study. PET showed increased focal uptake in 22 patients (88%): 11 of 14 (79%) ampullary tumors, and 100% of bile duct and duodenal tumors. PET showed a focal uptake in 11 of 12 patients without detectable mass at CT scan, and lymph node metastases in 6 patients. An SUV value of 2.7 discriminated adenomas or noninvasive cancers (n = 6) from invasive malignancies (n = 14). Follow-up evaluation including CT scan and PET was performed in 12 patients: PET showed recurrent disease not seen by CT in 4 patients, confirmed CT findings in 6 patients, and showed an unsuspected primary lung cancer in 1 patient and colon cancer in another patient. CONCLUSIONS: 18-FDG PET is very sensitive for detecting periampullary neoplasms. It may be useful to differentiate benign or borderline lesions from invasive tumors when no mass has been identified by traditional imaging. Finally, it is very useful in the follow-up evaluation of resected patients to identify recurrent disease or other malignancies.     

18-fluorodeoxyglucose positron emission tomography enhances computed tomography diagnosis of malignant intraductal papillary mucinous neoplasms of the pancreas

OBJECTIVE: To assess the reliability of 18-fluorodeoxyglucose positron emission tomography (18-FDG PET) in distinguishing benign from malignant intraductal papillary mucinous neoplasms (IPMNs) of the pancreas and its contribution to surgical decision making. SUMMARY BACKGROUND DATA: Pancreatic IPMNs are increasingly recognized, often as incidental findings, especially in people over age 70 and 80. Computed tomography (CT) and magnetic resonance (MR) are unreliable in discriminating a benign from a malignant neoplasm. 18-FDG PET as imaging procedure based on the increased glucose uptake by tumor cells has been suggested for diagnosis and staging of pancreatic cancer. METHODS: From January 1998 to December 2005, 64 patients with suspected IPMNs were prospectively investigated with 18-FDG PET in addition to conventional imaging techniques [helical-CT in all and MR and magnetic resonance cholangiopancreatography (MRCP) in 60]. 18-FDG PET was analyzed visually and semiquantitatively using the standard uptake value (SUV). The validation of the diagnosis was made by a surgical procedure (n = 44), a percutaneous biopsy (n = 2), main duct cytology (n = 1), or follow-up (n = 17). Mean and median follow-up times were 25 and 27.5 months, respectively (range, 12-90 months). RESULTS: Twenty-seven patients (42%) were asymptomatic. Forty-two patients underwent pancreatic resection, 2 palliative surgery, and 20 did not undergo surgery. An adenoma was diagnosed in 13 patients, a borderline tumor in 8, a carcinoma in situ in 5, and an invasive cancer in 21; in 17 patients a tumor sampling was not performed and therefore the histology remained undetermined. Positive criteria of increased uptake on 18-FDG PET was absent in 13 of 13 adenomas and 7 of 8 borderline IPMNs, but was present in 4 of 5 carcinoma in situ (80%) and in 20 of 21 invasive cancers (95%). Conventional imaging technique was strongly suggestive of malignancy in 2 of 5 carcinomas in situ and in 13 of 21 invasive carcinomas (62%). Furthermore, conventional imaging had findings that would be considered falsely positive in 1 of 13 adenomas (8%) and in 3 of 8 borderline neoplasms (37.5%). Therefore, positive 18-FDG PET influenced surgical decision making in 10 patients with malignant IPMN. Furthermore, negative findings on 18-FDG PET prompted us to use a more limited resection in 15 patients, and offered a follow-up strategy in 18 patients (3 positive at CT scan) for the future development of a malignancy. CONCLUSIONS: 18-FDG PET is more accurate than conventional imaging techniques (CT and MR) in distinguishing benign from malignant (invasive and noninvasive) IPMNs. 18-FDG PET seems to be much better than conventional imaging techniques in selecting IPMNs patients, especially when old and asymptomatic, for surgical treatment or follow-up.     

The utility of F-18 fluorodeoxyglucose whole body PET imaging for determining malignancy in cystic lesions of the pancreas

Previous studies have suggested that whole body positron-emission tomography (PET) can distinguish between benign and malignant cysts of the pancreas. Patients were identified (n=68) who had undergone whole body PET imaging for a cystic lesion of the pancreas between Jan. 1997 and May 2005. Cross-sectional imaging studies were reviewed by a single blinded radiologist, and positive PET studies were reviewed by a blinded nuclear medicine physician. Operative resection was performed in 21 patients (31%), and 47 patients were managed with radiographic follow-up. F-18 Fluorodeoxyglucose (FDG)-avid lesions were identified in eight of the 68 patients (12%). Within the resected group of patients (n=21), four of the seven patients (57%) with either in situ or invasive malignancy (adenocarcinoma: 3 of 5, papillary mucinous carcinoma: 1 of 2) had positive PET imaging (mean SUV, 5.9; range 2.5-8.0), and 2 of the 14 patients (14%) with benign lesions had positive PET imaging (serous cystadenoma, n=1, SUV=3.3; pseudocyst n=1, SUV=2.7). All lesions proven to be malignant with increased FDG uptake had highly suspicious findings on cross-sectional imaging. Within the group of resected patients, the sensitivity of PET for identifying malignant pathology was 57%, and the specificity was 85%. The sensitivity and specificity of PET for malignancy in this study was lower than previously reported, and PET findings did not identify otherwise occult malignant cysts. We do not believe whole body FDG-PET to be essential in the evaluation of cystic lesions of the pancreas.     

Value of 18-FDG-positron emission tomography/computed tomography before and after transarterial chemoembolization in patients with hepatocellular carcinoma undergoing liver transplantation: initial results

Introduction

Liver transplantation is the treatment of choice for various types of end-stage liver disease and the most appropriate alternative for the treatment of hepatocellular carcinoma (HCC)-associated liver cirrhosis. The aim of this study was to describe our initial experience with the use of 18-FDG positron emission tomography (PET)/computed tomography CT before and after transarterial chemoembolization (TACE) in HCC patients undergoing liver transplantation, seeking to predict the percentage of tumor necrosis achieved by TACE procedures.

Patients and Methods

From January 2007 through December 2009, 39 patients with HCC and liver cirrhosis were included in our liver transplantation program. We selected the 6 subjects who underwent 18-fluorodeoxyglucose PET/CT (18-FDG PET/CT) pre- and post-TACE.

Results

The median SUV (standarized uptake value) in the lesions studied were 4 (range, 2.79-6.95) before TACE with a median post-TACE SUV of 0 (range, 0-4). Among patients whose post-TACE SUV decreased to <3, the percentage of necrosis after studying the hepatectomy was >80%.

Conclusion

Performance of an 18-FDG PET/CT before and after TACE and comparison of SUV in patients with HCC awaiting liver transplantation provided valuable information regarding the effectiveness of TACE.     

Preoperative evaluation of thyroid nodules with 18FDG-PET/CT

BACKGROUND: Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography ((18)FDG-PET/CT) has become an important tool in the postoperative management of de-differentiated thyroid cancer. The utility of this imaging modality in the preoperative assessment of thyroid nodules is unclear. This study was designed to determine whether (18)FDG-PET/CT improves the preoperative diagnosis of thyroid nodules. METHODS: A total of 31 patients with 48 lesions underwent fine-needle aspiration and (18)FDG-PET/CT before surgical resection of thyroid nodules. PET/CT images were obtained 1 hour after intravenous administration of (18)FDG. Standard uptake values were calculated for regions of increased (18)FDG uptake. CT scans were evaluated to identify thyroid pathology. Final pathologic diagnoses were compared with PET/CT findings. RESULTS: Fifteen of 48 lesions were malignant and 33 were benign. Nine of 15 malignant lesions were (18)FDG-avid (sensitivity 60%). Thirty of 33 benign lesions were (18)FDG-cold (specificity 91%). Positive and negative predictive values were 75% and 83%, respectively. CONCLUSIONS: (18)FDG-PET/CT provides a high negative predictive value for malignancy, making this a potentially useful tool in the evaluation of thyroid nodules with indeterminate fine-needle aspiration. However further studies with larger sample sizes are needed to determine the true efficacy of this test.     

Imaging considerations in intraductal papillary mucinous neoplasms of the pancreas

With the widespread use of cross-sectional imaging, particularly computed tomography (CT) and magnetic resonance imaging (MRI), and the continuous improvement in the image quality of these techniques, the diagnosis of incidental pancreatic cysts has increased dramatically in the last decades. While the vast majority of these cysts are not clinically relevant, a small percentage of them will evolve into an invasive malignant tumor making their management challenging. Mucinous cystic neoplasms and intraductal papillary mucinous neoplasms (IPMN) are the most common pancreatic cystic lesions with malignant potential. Imaging findings on CT and MRI correlate tightly with the presence of malignant degeneration in these neoplasms. IPMN can be classified based on their distribution as main duct, branch duct or mixed type lesions. MRI is superior to CT in demonstrating the communication of a branch duct IPMN with the main pancreatic duct (MPD). Most branch duct lesions are benign whereas tumors involving the MPD are frequently associated with malignancy. The presence of solid nodules, thick enhancing walls and/or septae, a wide (> 1 cm) connection of a side-branch lesion with the MPD and the size of the tumor > 3 cm are indicative of malignancy in a branch and mixed type IPMN. A main pancreatic duct > 6 mm, a mural nodule > 3 mm and an abnormal attenuating area in the adjacent pancreatic parenchyma on CT correlates with malignant disease in main duct and mixed type IPMN. An accurate characterization of these neoplasms by imaging is thus crucial for selecting the best management options. In this article, we review the imaging findings of IPMN including imaging predictors of malignancy and surgical resectability. We also discuss follow-up strategies for patients with surgically resected IPMN and patients with incidental pancreatic cysts.     

18F-FDG PET/CT评价伽马刀治疗肿瘤疗效

目的探讨18F-FDG PET/CT在评价伽马刀治疗肿瘤疗效中的价值。方法对39例肿瘤术后复发患者,在伽马刀治疗前和治疗后3个月,根据CT显像的病灶大小、PET显像的平均标准摄取值（SUVmean）变化以及SUV变化率（△SUV）分别进行近期疗效判定。结果治疗前PET/CT全身检查后检出病灶并行伽马刀定位病灶65个,平均直径（3.32±3.57）cm;平均SUVmean5.92±2.62。伽马刀治疗3个月后复查,PET/CT检出病灶50个,平均直径（2.54±2.76）cm;平均SUVmean3.82±3.40。伽马刀治疗后病灶最大直径普遍较前缩小（P〈0.05）,伽马刀治疗后SUVmean显著降低（P〈0.001）。伽马刀治疗后CT显示的总有效率为38.46%（25/65）,PET SUVmean显示总有效率为55.38%（36/65）,二者之间差异有统计学意义（χ2=6.24,P〈0.05）。△SUV的总有效率为49.23%（32/65）。结论 18F-FDG PET/CT可以从病灶的大小和代谢两方面评价伽马刀治疗肿瘤的疗效。     

18F-FDG PET/CT在胆道系统恶性肿瘤中的应用

目的探讨~(18)F-FDG PET/CT诊断胆道系统恶性肿瘤的价值。方法回顾性分析34例临床疑似胆道恶性肿瘤患者的PET/CT影像资料,均获得术后病理结果,其中12例经手术切除淋巴结或淋巴结穿刺活检对18枚淋巴结获得病理诊断;与病理结果对照,计算PET/CT对胆道恶性病变原发灶、淋巴结转移的灵敏度、特异度、阳性预测值、阴性预测值及准确率。结果 34例中,31例为恶性病变,3例为良性病变。PET/CT诊断胆道恶性肿瘤原发灶的灵敏度100%(31/31),特异度66.67%(2/3),阳性预测值96.88%(31/32),阴性预测值100%(2/2),准确率97.06%(33/34)。胆道恶性病变原发灶最大标准摄取值(SUV_(max))为8.42±4.27;3例胆道良性疾病SUV_(max)分别为12.90、2.00及1.90。共18枚淋巴结获得病理结果,包括转移性淋巴结13枚,良性增生5枚。PET/CT诊断淋巴结转移的灵敏度76.92%(10/13),特异度60.00%(3/5),阳性预测值83.33%(10/12),阴性预测值50.00%(3/6),准确率72.22%(13/18)。结论 PET/CT对胆道系统恶性肿瘤的诊断具有重要价值。     

^18FDG—PET在肺癌诊断中的价值

目的研究氟脱氯葡萄糖F18-正电子发射计算机电子扫描(18FDG-PET)在鉴别肺部肿块性质和肺癌术前纵隔淋巴结转移分期中的应用价值.方法对34例肺部肿块患者进行18FDG-PET和CT检查,PET资料分别采用目测法和计算标准化摄取值(SUV)的半定量法进行分析,并同病理结果对照.结果目测法18FDG-PET诊断肺部肿块性质的敏感度、准确度分别是93%、85%;CT分别为63%、53%,2种方法差异有显著性意义(P＜0.05);半定量法准确度为74%,与CT相比,差异也有显著性意义(P＜0.05).肺部恶性肿块的SUV是4.4±1.9,良性为2.2±1.7,2者差异有显著性意义(P＜0.05).18FDG-PET和CT2种检查方法术前对纵隔淋巴结转移的分期与病理结果符合率分别为100%和78%,2者差异有显著性意义(P＜0.05).结论同CT相比,18FDG-PET能更准确地鉴别肺部肿块性质及确定纵隔淋巴结转移分期,是一种较好的无创性肺癌诊断技术.     

Standardized uptake values for breast carcinomas assessed by fluorodeoxyglucose-positron emission tomography correlate with prognostic factors

Several studies have revealed the diagnostic value of fluorodeoxyglucose-positron emission tomography for breast carcinomas. However, breast carcinomas display considerable variation in 18F-labeled 2-fluoro-2-deoxy-D-glucose uptake, and few papers have reported the clinical utility of the standardized uptake values (SUV). The purpose of this study is to investigate the relationship between SUV assessed by positron emission tomography (PET) and the clinicopathological characteristics of breast carcinoma. We reviewed 52 breast carcinomas of 45 patients presented at our department between January 2004 and July 2005. We compared the histopathological findings of the breast carcinomas with the preoperative SUV. Of the 52 breast carcinomas, 49 (94%) were detected by preoperative PET. A positive correlation was found between the SUV and tumor size (P < 0.01), histological grade (P < 0.01), the expression of the estrogen receptor (P < 0.001), progesterone receptor (P < 0.01), and p53 (P < 0.01). The number of metastatic axillary lymph nodes (r = 0.73; P < 0.0001) and the MIB-1 labeling rates (r = 0.5; P < 0.01) correlated with the SUV of the breast carcinomal. No relationship existed between the SUV and the following: histological tumor types (P = 0.07), human epidermal growth factor receptor-2 status (P = 0.10), and the presence of metastatic lymph nodes (P = 0.10). The SUV of the breast carcinomas correlate with several histopathological and immunohistochemical prognostic factors. We can obtain information on the degree of malignancy of the carcinoma and prognostic factors by preoperative PET examination.     

肾上腺肿瘤44例分析

目的提高对肾上腺肿瘤的诊断水平。方法肾上腺肿瘤共44例，11例行18F-氟脱氧葡萄糖（18F—FDG）PET／CT、CT及MRI检查，余行CT和18F—FDG PET／CT检查，所有病例均行高血压试验和24h尿肾上腺素2项检测，术后病理或临床随访确诊。结果18F—FDG PET／CT对肿瘤良恶性诊断的敏感性、特异性分别为93．7％、100％，肿瘤诊断准确性为82．9％。CT分别为87．5％、96．4％和77．3％。MRI的肿瘤诊断准确性为81．8％。血浆醛固酮最高浓度在各肿瘤中差异无统计学意义（P〉0．05）。髓质肿瘤与其他肾上腺肿瘤相比尿去甲基肾上腺素（NMN）、尿甲氧基肾上腺素（MN）、收缩压、舒张压差异均有统计学意义（P〈0．05）。以3．1作为SUV临界值，得出PET／CT区分肿瘤良恶性敏感性和特异性最佳，分别为100％和96．2％。结论18F—FDGPET／CT在诊断肾上腺肿瘤良恶性上优于MRI和CT。高血压和尿NMN／MN成3倍以上升高对嗜铬细胞瘤的诊断意义重大。髓脂瘤、囊肿和嗜铬细胞瘤运用CT或MRI能较好诊断，非功能性和皮质肿瘤以PET／CT诊断为佳。     

Synchronous primary epithelial tumors of the pancreas

INTRODUCTIONPancreatic incidentalomas are diagnosed at increased rates due to advanced pancreatic imaging. Coexistence of such lesions with another pancreatic pathology, however, is uncommon and their management might be perplexed by the anatomical location and the histological features of the lesion.PRESENTATION OF CASEA patient with obstructive jaundice was diagnosed with adenocarcinoma of the pancreatic head and underwent routine pancreatic imaging (CT) which revealed the coexistence of a small cystic lesion at the pancreatic body. Further investigation with MRCP and ERCP was unable to confirm a benign lesion and total pancreatoduodenectomy was performed. Histological examination showed a rare type of mixed serous–mucinous cystadenoma of borderline malignancy at the pancreatic body coexistent with an adenocarcinoma of the pancreatic head.DISCUSSIONCoexistence of a peripheral pancreatic cystic tumor with a ductal adenocarcinoma of the pancreatic head is a very rare incidence in medical literature. The management of the peripheral lesion is not straightforward and there can be uncertainty as to the extent of the pancreatic resection that may be required.CONCLUSIONAppropriate preoperative imaging has a significant impact on the definitive management of synchronous pancreatic tumors. Implications of a common pathogenetic pathway are also raised for this rare occurrence of two primary epithelial pancreatic tumors.     

Analysis of Pancreatic Cyst Fluid

Pancreatic cysts are extremely common, and are identified in between 2% to 13% on abdominal imaging studies. Most pancreatic cysts are pseudocysts, serous cystic neoplasms, mucinous cystic neoplasms, or intraductal papillary mucinous neoplasms. The management of pancreatic cysts depends on whether a cyst is benign, has malignant potential, or harbors high-grade dysplasia or invasive carcinoma. The diagnosis of pancreatic cysts, and assessment of risk of malignant transformation, incorporates clinical history, computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound, and fine-needle aspiration of cyst fluid. This article reviews the cyst fluid markers that are currently used, as well as promising markers under development.     

Positron emission tomography does not add to computed tomography for the diagnosis and staging of pancreatic cancer

BACKGROUND: Positron emission tomography (PET) has been proposed for pancreatic cancer diagnosis and staging. METHODS: 112 patients with suspected pancreatic cancer underwent 18F-fluoro-2-deoxy-D-glucose gamma camera PET and computed tomography (CT), of whom 62 also had laparoscopic ultrasonography and 70 underwent abdominal exploration for potential resection. The final diagnosis was malignancy in 78 and benign disease in 34 patients (25 with chronic pancreatitis). RESULTS: The diagnostic sensitivity and specificity for PET were 73 and 60% compared to 89 and 65% for CT respectively (Cohen's kappa = 0.59). In 30 patients CT was equivocal with cancer in 14 and benign disease in 16. PET correctly diagnosed 13 of these patients (cancer in 6 and benign disease in 7), interpreted 4 as equivocal (cancer in 3 and benign disease in 1) but was incorrect in the remaining 13 patients (cancer in 5 and benign disease in 8). The sensitivity and specificity for detecting small volume metastatic disease were 20 and 94% for CT and 22 and 91% for PET, respectively. CONCLUSION: PET had a similar accuracy to that of CT for imaging pancreatic cancer but it did not provide any additional information in patients with equivocal CT findings and currently would seem of little benefit for the staging of pancreatic cancer.     

Risk of Malignancy in Resected Cystic Tumors of the Pancreas ≤3 cm in Size: Is it Safe to Observe Asymptomatic Patients? A Multi-institutional Report

Recent international consensus guidelines propose that cystic pancreatic tumors less than 3 cm in size in asymptomatic patients with no radiographic features concerning for malignancy are safe to observe; however, there is little published data to support this recommendation. The purpose of this study was to determine the prevalence of malignancy in this group of patients using pancreatic resection databases from five high-volume pancreatic centers to assess the appropriateness of these guidelines. All pancreatic resections performed for cystic neoplasms ≤3 cm in size were evaluated over the time period of 1998–2006. One hundred sixty-six cases were identified, and the clinical, radiographic, and pathological data were reviewed. The correlation with age, gender, and symptoms (abdominal pain, nausea and vomiting, jaundice, presence of pancreatitis, unexplained weight loss, and anorexia), radiographic features suggestive of malignancy by either computed tomography, magnetic resonance imaging, or endoscopic ultrasound (presence of solid component, lymphadenopathy, or dilated main pancreatic duct or common bile duct), and the presence of malignancy was assessed using univariate and multivariate analysis. Among the 166 pancreatic resections for cystic pancreatic tumors ≤3 cm, 135 cases were benign [38 serous cystadenomas, 35 mucinous cystic neoplasms, 60 intraductal papillary mucinous neoplasms (IPMN), 1 cystic papillary tumor, and 1 cystic islet cell tumor], whereas 31 cases were malignant (14 mucinous cystic adenocarcinomas and 13 invasive carcinomas and 4 in situ carcinomas arising in the setting of IPMN). A greater incidence of cystic neoplasms was seen in female patients (99/166, 60%). Gender was a predictor of malignant pathology, with male patients having a higher incidence of malignancy (19/67, 28%) compared to female patients (12/99, 12%; p < 0.02). Older age was associated with malignancy (mean age 67 years in patients with malignant disease vs 62 years in patients with benign lesions (p < 0.05). A majority of the patients with malignancy were symptomatic (28/31, 90%). Symptoms that correlated with malignancy included jaundice (p < 0.001), weight loss (p < 0.003), and anorexia (p < 0.05). Radiographic features that correlated with malignancy were presence of a solid component (p < 0.0001), main pancreatic duct dilation (p = 0.002), common bile duct dilation (p < 0.001), and lymphadenopathy (p < 0.002). Twenty-seven of 31(87%) patients with malignant lesions had at least one radiographic feature concerning for malignancy. Forty-five patients (27%) were identified as having asymptomatic cystic neoplasms. All but three (6.6%) of the patients in this group had benign disease. Of the patients that had no symptoms and no radiographic features, 1 out of 30 (3.3%) had malignancy (carcinoma in situ arising in a side branch IPMN). Malignancy in cystic neoplasms ≤3 cm in size was associated with older age, male gender, presence of symptoms (jaundice, weight loss, and anorexia), and presence of concerning radiographic features (solid component, main pancreatic duct dilation, common bile duct dilation, and lymphadenopathy). Among asymptomatic patients that displayed no discernable radiographic features suggestive of malignancy who underwent resection, the incidence of occult malignancy was 3.3%. This study suggests that a group of patients with small cystic pancreatic neoplasms who have low risk of malignancy can be identified, and selective resection of these lesions may be appropriate.     

~(18)FDG-PET在肺癌诊断中的价值

目的　研究氟脱氯葡萄糖F18 正电子发射计算机电子扫描 (1 8FDG PET)在鉴别肺部肿块性质和肺癌术前纵隔淋巴结转移分期中的应用价值。　方法　对 34例肺部肿块患者进行1 8FDG PET和CT检查 ,PET资料分别采用目测法和计算标准化摄取值 (SUV)的半定量法进行分析 ,并同病理结果对照。　结果　目测法1 8FDG PET诊断肺部肿块性质的敏感度、准确度分别是 93%、85 % ;CT分别为 6 3%、5 3% ,2种方法差异有显著性意义 (P <0 0 5 ) ;半定量法准确度为 74% ,与CT相比 ,差异也有显著性意义 (P <0 0 5 )。肺部恶性肿块的SUV是 4 4± 1 9,良性为 2 2± 1 7,2者差异有显著性意义 (P <0 0 5 )。1 8FDG PET和CT 2种检查方法术前对纵隔淋巴结转移的分期与病理结果符合率分别为10 0 %和 78% ,2者差异有显著性意义 (P <0 0 5 )。　结论　同CT相比 ,1 8FDG PET能更准确地鉴别肺部肿块性质及确定纵隔淋巴结转移分期 ,是一种较好的无创性肺癌诊断技术。     

胰腺囊性肿瘤术前良恶性判断

随着影像诊断技术的广泛应用和改进,胰腺囊性肿瘤（PCN）的诊断率不断增加。常见的胰腺囊性肿瘤包括浆液性囊腺瘤（SCN）、黏液性囊腺瘤（MCN）和导管内乳头状黏液性肿瘤（IPMN）以及囊实性假乳头状肿瘤（SPN）,一旦怀疑为恶性时,均应行根治性手术切除。PCN的术前诊断和良恶性判断十分重要,目前主要依靠临床表现、影像学检查和实验室检查。当临床发现老年男性病人、血清肿瘤标记物CA19-9升高、伴有巨大胰腺肿块、体重下降、有特征性影像学表现者,应考虑恶性肿瘤的可能。主要依靠术后病理、经超声内镜下囊液抽取分析和穿刺组织活检确诊,包括肿瘤相关DNA、MicroRNA和蛋白质标记物的分析。     

Efectividad diagnóstica de la tomografía por emisión de positrones con 18fluorodeoxiglucosa asociada a tomografía axial en la discriminación de benignidad o malignidad de las lesiones suprarrenales

IntroductionThe usefulness of 18fluorodeoxyglucose positron emission tomography combined with axial tomography (PET-CT) in diagnosing whether adrenal tumours are benign or malignant is assessed.Material and methodsA retrospective study conducted between June 2005 and May 2009 on a consecutive series of patients on whom a PET-CT scan was performed to study suspected malignant adrenal disease. Focal uptakes were assessed, along with the maximum standard uptake value (SUV), and the ratio of the maximum adrenal/hepatic value. The sensitivity, specificity, positive and negative predictive value of the test, the maximum adrenal uptake values and the ratio for those where the diagnostic yield was maximum.ResultsFifteen patients were included. The final diagnosis showed malignancy in eight and seven were benign. Ten patients had adrenal uptake: three in benign lesions and seven in neoplasias, with a mean uptake value of 6.3 (3.2 in benign lesions and 9.0 in malignant lesions). The mean adrenal/hepatic ratio was 1.8 (0.9 in benign and 2.6 in malignant lesions). When the presence of adrenal uptake is associated with a final diagnosis of malignancy, we obtained a sensitivity of 87.5%, a specificity of 57.1%, and a positive and negative predictive value of 70% and 80%, respectively. An SUV cut-off value of 6, or an adrenal/hepatic uptake ratio of 2, gave a sensitivity of 75%, a specificity of 100%, and a positive and negative predictive value of 100% and 77.7%, respectively.ConclusionsPET-CT has a high ability to discriminate between benign and malignant lesions in the adrenal disease studied.