Role of FDG-PET in surgical management of patients with colorectal liver metastases

BACKGROUND: [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) is reported to change the management in 20-56% of patients with recurrent or metastatic colorectal cancer. It is not clear if FDG-PET has a role in all such patients or only a subgroup. The aim of the present study was to assess the influence of FDG-PET on the surgical management of patients with known or suspected colorectal liver metastases. METHODS: Patients undergoing FDG-PET for investigation of known or suspected colorectal liver metastases were identified from a South Australian database. Case notes were reviewed retrospectively to determine the influence of FDG-PET findings on patient management. Findings from FDG-PET scanning were compared with findings from conventional diagnostic investigations and operative findings. RESULTS: Overall, in four of 16 patients (25%) management was influenced by FDG-PET findings. FDG-PET altered management in four of eight (50%) patients with non-diagnostic liver lesions on computed tomography (CT) or with elevated carcinoembryonic antigen levels but no liver lesion on CT. In all eight patients with CT diagnosed resectable liver metastases, the addition of FDG-PET did not influence the management. CONCLUSIONS: The findings support the use of FDG-PET in the assessment of selected patients with suspected colorectal liver metastases and equivocal findings on conventional diagnostic investigation.     

Histological verification of positive fluorine-18 fluorodeoxyglucose findings in patients with differentiated thyroid cancer

Fluorine-18 fluorodeoxyglucose and positron emission tomography (FDG-PET) is a new imaging modality used in the follow-up of patients with differentiated thyroid cancer if the results of ¹³¹I scintigraphy are negative in spite of an elevated thyroglobulin level. The aim of this retrospective analysis was to estimate the value of FDG-PET regarding the operability of patients with positive findings. From January 1994 to October 1997, we investigated 60 patients with differentiated thyroid carcinoma by FDG-PET. Thirteen patients were operated on after positive findings. Most of these lesions were suspected of having lymph-node involvement or local recurrences in the thyroid bed. One patient showed a solitary distant metastasis in the scapula. Thirteen of 16 operations in these 13 patients confirmed the suspected involvement of thyroid cancer. The false-positive findings were caused by inflamed lymph nodes in two cases and benign thymus tissue in one case. We conclude that PET is a useful diagnostic tool to guide early surgical therapy in patients with ¹³¹I-negative differentiated thyroid carcinoma. Received: 6 February 1998     

Comparison of Linear Array Endoscopic Ultrasound and Helical Computed Tomography for the Staging of Periampullary Malignancies

Background: The purpose of this study was to compare linear array endoscopic ultrasound (EUS) and helical computed tomography (CT) scan in the preoperative local staging evaluation of patients with periampullary tumors.Methods: Patients evaluated with EUS and CT for suspected periampullary malignancies from 1996 to 2000 were analyzed. Surgical/pathology staging results were the reference standard.Results: Forty-eight patients (28 men and 20 women; mean age, 62 ± 4.9 years; range, 18–90 years) were identified. Malignancy was histologically confirmed in 44 patients. Parameters evaluated included tumor size, lymph node metastases, and major vascular invasion. EUS was significantly more sensitive (100%), specific (75%), and accurate (98%) than helical CT (68%, 50%, and 67%, respectively) for evaluation of the periampullary mass (P < .05). In addition, EUS detected regional lymph node metastases in more patients than helical CT. Sensitivity, specificity, and accuracy of EUS were 61%, 100%, and 84%, in comparison to 33%, 92%, and 68%, respectively, with CT. Major vascular involvement was noted in 9 of 44 patients. EUS correctly identified vascular involvement in 100% compared with 45% with CT (P < .05).Conclusions: Linear array EUS was consistently superior to helical CT in the preoperative local staging of periampullary malignancies.Presented in part at the Society of Surgical Oncology Parallel Session, Washington, DC, March 2001.     

Improved Staging With Pretreatment Positron Emission Tomography/Computed Tomography in Low Rectal Cancer

Background ¹⁸F-Fluorodeoxyglucose (FDG)-positron emission tomography (PET) and computed tomography (CT) are widely accepted in the evaluation for metastatic or recurrent rectal cancer. Only spiral CT and transrectal ultrasonography (TRUS) are routinely used in the initial evaluation of primary rectal cancer. We wished to determine whether PET/CT could provide additional information in patients undergoing standard evaluation for primary rectal cancer. Methods Thirty-seven patients (mean age, 58 years; range, 26–90 years) with a previously untreated rectal cancer underwent TRUS or magnetic resonance imaging, spiral CT, and FDG-PET/CT. The tumor location (low, ≤6 cm; mid, 7–10 cm; or high, ≥10 cm) and carcinoembryonic antigen level were recorded. Discordant findings between spiral CT and FDG-PET/CT were confirmed by histological analysis or imaging follow-up. Results FDG-PET/CT identified discordant findings in 14 patients (38%), and this resulted in upstaging of 7 patients (50%) and downstaging of 3 patients (21%). Although node-positive disease on TRUS/magnetic resonance imaging was associated with discordant FDG-PET/CT findings, this was not statistically significant. Discordant PET/CT findings were significantly more common in patients with a low rectal cancer than in those with mid or high rectal cancer (13 vs. 1; P = .0027). The most common discordant finding was lymph node metastasis (n = 7; 50%). Histological confirmation of discordant FDG-PET/CT findings was performed in seven patients, and in no case did FDG-PET/CT prove to be inaccurate. Discordant PET/CT findings resulted in a deviation in the proposed treatment plan in 27% of patients (n = 10). Conclusions FDG-PET/CT frequently yields additional staging information in patients with low rectal cancer. Improved accuracy of pretreatment imaging with FDG-PET/CT will allow for more appropriate stage-specific therapy. Presented at the Annual Meeting of the Society of Surgical Oncology, Atlanta, Georgia, March 3–6, 2005.     

增强CT和PET/CT对胰腺癌诊断及分期中的价值

目的 探讨增强CT和PET/CT对胰腺癌诊断及分期中的价值.方法 回顾性分析安徽医科大学第一附属医院普外科2009年10月至2013年10月间收治47例手术治疗的胰腺占位患者资料.术前均行CA19-9检查、腹部增强CT扫描及全身PET/CT扫描,比较增强CT与PET/CT在胰腺癌诊断及分期中价值.结果 47例患者中,确诊胰腺癌41例,非胰腺癌6例.CA19-9、增强CT和PET/CT对胰腺癌诊断的灵敏度分别为78.0％、80.4％和95.1％,PET/CT灵敏度优于CA19-9和增强CT,差异有统计学意义（P值分别为0.023和0.043）;在胰周淋巴结转移判断方面,PET/CT和增强CT的灵敏度分别为75.0％和41.6％,二者差异有统计学意义（P=0.019）;在肝转移判断方面,PET/CT和增强CT诊断的灵敏度分别为80.0％和60.0％,二者差异无统计学意义（P=1.0）.结论 PET/CT对胰腺癌诊断有较高灵敏度,显著优于增强CT.当肿瘤SUV值升高,PET/CT诊断仍应注意结合CA19-9、增强CT甚至MRI综合判断;PET/CT有助于发现淋巴结和远处器官转移病灶,获得更加准确的术前分期,从而避免诊断性剖腹探查手术.     

Combined [<Superscript>18</Superscript>F]Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography (FDG-PET/CT) for Detection of Recurrent, <Superscript>131</Superscript>I-Negative Thyroid Cancer

Background Whole-body ¹³¹I scintigraphy (WBS) and serial thyroglobulin measurement (Tg) are standard methods for detecting thyroid cancer recurrence after total/near total thyroidectomy and ¹³¹I ablation. Some patients develop elevated Tg (Tg-positive) or there is clinical suspicion of recurrence, but WBS are negative (WBS-negative). This may reflect non-iodine-avid recurrence or metastasis. In 2002, the Centers for Medicare and Medicaid Services (CMS) approved positron emission tomography with [¹⁸F]fluorodeoxyglucose (FDG-PET) for Tg-positive/WBS-negative patients with follicular-cell-origin thyroid cancer. Limited data are available regarding the performance of combined FDG-PET/computed tomography (FDG-PET/CT) for detecting recurrent thyroid cancer in WBS-neg patients. Methods This retrospective review of prospectively collected data analyzed 65 patients who had FDG-PET/CT for suspected thyroid cancer recurrence (April 1998–August 2006). Patients were WBS-negative but were suspected to have recurrence based on Tg levels or clinical grounds. Suspected FDG-PET/CT abnormalities were reported as benign or malignant. Lesions were ultimately declared benign or malignant by surgical pathology or clinical outcome (disease progression). Results Of 65 patients who underwent FDG-PET/CT, 47 had positive FDG-PET/CT. Of the positive FDG-PET/CT, 43 studies were true positives, with 21 (49%) confirmed pathologically by surgical resection. The four false positives (3/4 confirmed pathologically) included an infundibular cyst, an inflamed supraclavicular cyst, pneumonitis, and degenerative disc disease. Of the 18 FDG-PET/CT studies that were negative, 17 were true negatives and one was a false negative (metastatic papillary carcinoma). Thus, FDG-PET/CT demonstrated a patient-based sensitivity of 98%, specificity of 81%, positive predictive value of 91%, and negative predictive value of 94%. Conclusions FDG-PET/CT is useful for detecting thyroid cancer recurrence in WBS-negative patients, and can assist decision making.     

Positron Emission Tomography for Staging Esophageal Cancer: Does It Lead to a Different Therapeutic Approach?

Accurate preoperative staging is essential for the indication and selection of the appropriate surgical procedure in patients with esophageal cancer. The present prospective study was designed to determine if the preoperative use of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) increases the accuracy of staging esophageal cancer compared with computed tomography (CT) and if it thereby leads to a different therapeutic approach. A total of 58 patients, 46 men and 12 women (mean age 61 years), with histologic proof of esophageal carcinoma underwent FDG-PET of the neck, chest, and abdomen, as well as CT of the chest and abdomen, to determine tumor stage. FDG-PET and CT data were compared with each other and with pathohistologic findings. Sensitivity, specificity, and overall accuracy for detecting histologically verified lymph node and distant metastases were calculated for FDG-PET and CT. FDG-PET showed a higher specificity, whereas CT had higher accuracy for detecting both abdominal (73% vs. 59%) and thoracic (73% vs. 63%) lymph node metastases. The accuracy of detecting blood-borne and lymphatic distant metastases was identical for CT and FDG-PET imaging (50%). FDG-PET had a higher specificity than CT (87% vs. 13%) but lower sensitivity (35% vs. 67%). FDG-PET did not provide new information on the indication for surgery, nor was it helpful for choosing the appropriate surgical procedure in patients with esophageal carcinoma. In view of the relatively high cost of FDG-PET examinations, the use of this modality is indicated primarily in patients with inconclusive CT findings or for scientific research projects. Higher sensitivity as a result of tumor-affinity radiopharmaceuticals and optimized apparatus resolution, in addition to the advantages offered by whole-body PET scanning, may lead to new indications for this staging procedure in the future.     

Use of Positron Emission Tomography in Surgery Follow-Up of Esophageal Cancer

Introduction  Although the prognosis of patients with esophageal cancer has been improved by extended dissection, the incidence of recurrence still remains high. In esophageal cancer, positron emission tomography (PET) using ¹⁸F-fluorodeoxyglucose (FDG) already demonstrated to be useful for initial staging and monitoring response to therapy. This prospective study compared the ability of FDG-PET and conventional imaging to detect early recurrence of esophageal cancer after initial surgery in asymptomatic patients. Materials and Methods  Between October 2003 and September 2006, 41 patients with esophageal cancer were included in a prospective study after initial radical esophagectomy. FDG-PET, thoracoabdominal computed tomography (CT), abdominal ultrasonography, and endoscopy were performed every 6 months after initial treatment. Results and Discussion  Twenty-three patients had recurrent disease (56%), mostly within the first 6 months after surgery (70%). Despite two false-positive scans due to postoperative changes, FDG-PET was more accurate than CT (91% vs. 81%, p = 0.02) for the detection of recurrence with a sensitivity of 100% (vs. 65%), a specificity of 85% (vs. 91%), and a negative predictive value of 100% on a patient-by-patient-based analysis. For the detection of locoregional recurrence, FDG-PET was more accurate than CT (96.2% vs. 88.9%). FDG-PET was also more accurate than CT for the detection of distant metastases (92.5% vs. 84.9%), especially when involving either bones (100%) or liver (98.1%). A lower sensitivity of FDG-PET (57%) for the early detection of small lung metastases did not affect patient management (accuracy = 92.5%). Conclusion  FDG-PET appears to be very useful for the systematic follow-up of asymptomatic patients after esophagectomy with an initial scan performed 6 months after surgery. Presented at the Forty-sixth Annual Meeting of The European Society of Nuclear Medicine, Athens, Greece, September 30–October 4, 2006 (oral presentation).     

The sensitivity of F-fluorodeoxyglucose positron emission tomography in the evaluation of metastatic pulmonary nodules

Objective: Pulmonary metastasectomy is beneficial in select patients. The sensitivity of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) for pulmonary metastasis is unknown. The aims of the study were to determine the accuracy of FDG-PET in detecting pulmonary metastasis and identify factors affecting sensitivity. Methods: All patients undergoing metastasectomy from September 2002 through December 2006 who had both chest computed tomography (CT) and FDG-PET scans or a fused CT/FDG-PET within 6 weeks prior to surgery were reviewed. Univariate and multivariate analysis were performed to determine predictors of positivity. Results: There were 83 patients (41 men, 42 women) who had 104 resections. Median age was 61 years (range, 32–87). In total 154 nodules were resected; 1 nodule in 47 patients and multiple in 36. Histopathology was adenocarcinoma in 94 nodules, sarcoma in 18, squamous cell carcinoma in 15, renal cell carcinoma in 7 and other in 20. At least one nodule was FDG-PET positive in 68 patients (81.9%). True positive FDG-PET was found in 104 nodules (67.5%) while 50 were false negative (32.5%). Multivariate analysis revealed tumor diameter and grade correlated with increased sensitivity of FDG-PET. Conclusion: FDG-PET is positive in only 67.5% of metastatic pulmonary nodules. Nodule size and grade affect the sensitivity of FDG-PET for metastatic pulmonary nodules. FDG-PET is not a sensitive test in the evaluation of patients considered for pulmonary metastasectomy. Moreover, a negative FDG-PET should not be used to rule out metastatic disease.     

Positron-emission tomography with 18F-2-fluoro-2-deoxy-D-glucose (18FDG-PET) in the diagnosis of retroperitoneal lymph-node metastases from testicular tumors

Summary In 1991, this prospectively designed study was started to assess the potentials of positron emission tomography with ¹⁸FDG in the diagnostic workup for the detection of lymph node metastases in testicular cancer, since there were no data available concerning this subject at this time. In 54 patients (27 patients with pure seminoma, 27 patients with non-seminomatous tumors) ¹⁸FDG-PET results were compared with the findings obtained with abdominal computed tomography, serum level of tumor markers (AFP, β -HCG), and the histopathological findings after primary or post-chemotherapy retroperitoneal lymph node dissection. In 21 patients with pure seminoma (clinical stage I according to the Lugano classification) ¹⁸FDG-PET results were identical with those of the abdominal computed tomography, so PET does not add relevant informations in this group of patients. In 7 patients presenting with non-seminomatous testicular cancer (stage I), PET was not able to detect the existing micrometastases in 4 patients. In 1/7 case PET examination showed a suspicious focal lesion, this lymph node had 2 micrometastases within inflammatory changes. In 1/7 patient ¹⁸FDG-PET definitely revealed metastatic lesions, while the CT scans where judged to be unobtrusive and tumor marker levels were within the normal range. In the 4 patients with pure seminomas stage II B and II C (N = 6), that have undergone retroperitoneal lymph node dissection following chemotherapy, ¹⁸FDG-PET correctly predicted absence of tumor in 3 out of these 4, and in 1/4 patient the benign nature of a persistent large tumor after two cycles of polychemotherapy was correctly identified wich eventually turned out to be a ganglioneuroma. This lesion falsely was classified as malignant tumor with abdominal computed tomography, and in 2/4 patients post-chemotherapy residual retroperitoneal lesions in the CT scans could not be assessed exactly whether or not malignant tumor was present. In 20 patients presenting with non-seminomatous testicular cancer (stage II and III) ¹⁸FDG-PET was able to demonstrate therapeutic effects of chemotherapy by showing decreasing tracer activity in those regions, that had hypermetabolic foci prior to chemotherapy. It became evident in testicular cancer that there is a single entity which is not characterized by increased glucose metabolism, the mature teratoma. In lesions detected by abdominal computed tomography which do not present increased ¹⁸FDG uptake, mature teratoma as well as scar/necrosis or rare other tumors with normal glucose metabolism can be supposed, but additional characteristics based on different ¹⁸FDG uptake were not observed. In 1/20 case post-chemotherapy PET scan detected a hypermetabolic lesion, which was suspicious for metastatic spread, but in the histopathological examination this lesion was identified as inflammatory tissue reaction. Based on the data reported here in ¹⁸FDG-PET cannot be considered a standard diagnostic tool in the staging examinations in testicular cancer. It is of clinical relevance in patients who present residual tumor after chemotherapy. In this situation ¹⁸FDG-PET is helpful in deciding whether or not a residual mass post-chemotherapy contains active tumor. ¹⁸FDG-PET can not replace retroperitoneal lymph node dissection for staging purposes.      

Pitfalls of Positive Findings in Staging Esophageal Cancer With F-18-Fluorodeoxyglucose Positron Emission Tomography

Background: 18-F-fluorodeoxyglucose positron emission tomography (FDG-PET) is valuable in staging of esophageal cancer. However, FDG-PET may falsely upstage patients leading to incorrect exclusion from surgical treatment. This study was performed to determine the false-positive rate and possible causes.Methods: The rate of false-positive lesions on FDG-PET was documented in 86 out of a group of 98 patients. Lesions were defined as false positive when pathological examination was negative or as absence of tumor activity within 6 months of follow-up. To evaluate the influence of a learning curve on the false-positive rate, the PET scans were revised recently.Results: False-positive lesions were found in 13 patients (13 of 86; 15%). FDG-PET incorrectly revealed only locoregional node metastases in 5 patients in whom surgery with curative intent was performed. Ten lesions in the other 8 patients were classified as distant organ or as nonregional node metastases (M1a/1b). Finally, 5 patients upstaged to M1a/1b underwent a curative resection. The number of false-positive lesions decreased from 16 to 5 (6%) after revision.Conclusions: Proper interpretation of FDG-PET in staging esophageal cancer is impeded by false-positive results. Even after completion of the learning curve, positive FDG-PET findings still have to be confirmed by additional investigations.     

False positive accumulation in 18F fluorodeoxyglucose positron emission tomography scan due to sarcoid reaction following induction chemotherapy for lung cancer

We present a case of lung cancer that showed false positive accumulation in an ¹⁸F fluorodeoxyglucose positron emission tomography (FDG-PET) scan following induction chemotherapy for suspected metastasis and progression of malignancy. A 66-year-old man was diagnosed with squamous cell carcinoma in the lung, classified as clinical stage IIIA (T2N2M0), and underwent induction chemotherapy. An FDG-PET scan prior to chemotherapy demonstrated accumulation only in the tumor, whereas following treatment it revealed a strong accumulation not only in the tumor, but also in the supraclavicular lymph nodes, which indicated lymph node metastasis. The patient underwent a biopsy of the right supraclavicular lymph node and mediastinoscopy, after which all dissected lymph nodes showed sarcoid reactions and no tumor cells were found pathologically. We concluded that when evaluating the effect of induction chemotherapy for malignancy, a sarcoid reaction might lead to the false positive accumulation of FDG.     

Fluorodeoxyglucose positron emission tomography integrated with computed tomography to determine resectability of primary lung cancer

PURPOSE: Fluorodeoxyglucose positron emission tomography integrated with computed tomography (FDGPET/CT) was evaluated as a routine staging technique for primary lung cancer. MATERIALS AND METHODS: We prospectively compared FDG-PET/CT in determining clinical stage and surgical indication with conventional staging not including positron emission tomography (PET). A total of 50 consecutive patients diagnosed with primary lung cancer by cytological or histological examination were studied; 20 of them underwent surgery. RESULTS: Discrepancies between the two staging methods were observed in 14 patients (28%). The stage assigned by PET increased in 12 cases (24%) and decreased in 2 (4%). PET staging was accurate in eight cases with otherwise undetected distant metastases (M1) but was incorrect in six cases, including five where it overdiagnosed nodal metastases (N). Two clinical N3 patients (4%) would have missed a chance of surgery if the surgical indication had been determined by PET staging alone. According to our criteria for surgery, other patients were assigned correctly to surgery by PET staging. The maximum standard uptake value (maxSUV) of all primary lesions ranged from 0 to 23.0 (mean +/- SD, 8.0 +/- 4.4). The mean maxSUV among surgical cases (5.8 +/- 3.6) was significantly smaller than among nonsurgical cases (9.5 +/- 4.2) (P < 0.05). CONCLUSION: Staging examination including FDG-PET/CT and brain magnetic resonance imaging ordinarily can determine the clinical stage and resectability of primary lung cancer. False-positive findings in regional lymph nodes, possibly reflecting past infectious disease, are the most important remaining problem.     

Sensitivity and specificity of FDG PET-CT scan in detecting lymph node metastasis in operable periampullary tumours in correlation with the final histopathology after curative surgery

18F-Fluorodeoxyglucose-positron emission tomography/computerised tomography (FDG-PET/CT) was investigated for evaluation of periampullary tumours and other gastrointestinal neoplasms. The aim of this study was to evaluate the utility of FDG-PET/CT for detection of lymph node metastasis in periampullary tumours by comparing the preoperative FDG-PET/CT scan finding with postoperative histopathology of lymph nodes. Study was done on 24 patients with diagnosis of periampullary carcinoma either proven or suspected on conventional radiology. Standard uptake value (SUV) were measured for lymph node areas with uptake in FDG-PET/CT and compared with histopathological lymph node status. For detection of lymph node metastasis, FDG-PET/CT with cutoff value SUV max ≥2.0 had a sensitivity of 71.4 % and specificity of 77.8 % and that for SUV max ≥2.5 and 2.8 were 57.1, 42.9 and 77.8, 77.8 %, respectively. The sensitivity and specificity of FDG-PET/CT at each lymph node groups were 72 and 89 % in peripancreatic area, 100 and 93 % in hepatoduodenal area and 100 and 100 % in aortocaval area at SUV max ≥2.0, respectively. At SUV max ≥2.5 the values were 57 and 89 % in peripancreatic area, 100 and 93 % in hepatoduodenal area and 100 and 93 % in aortocaval area. FDG-PET-CT has a possible role in detection of lymph node metastasis in periampullary carcinomas and may be used as a guide for possible lymphadenectomy during surgery and for prognostic purpose.     

Silk suture granuloma with false-positive findings on PET/CT accompanied by peritoneal metastasis after colon cancer surgery

IntroductionSuture granuloma is a rare benign tumor caused by suture material, which usually appears several months or years after surgery.Presentation of caseA 71-year-old man underwent sigmoidectomy and partial hepatectomy (S6) for sigmoid colon cancer and synchronous liver metastasis at a previous hospital. At 4 postoperative months, surveillance computed tomography (CT) revealed a suspicious tumor at the hepatic resection stump. He was referred to our hospital for further examinations and treatments. Positron emission tomography/CT (PET/CT) revealed abnormal hepatic F-18 fluorodeoxyglucose (FDG) uptake below the diaphragm at the S5/S8 surface. Peritoneal metastasis was suspected and surgery was performed. White nodules were found in the Douglas pouch. A diagnosis of adenocarcinoma was confirmed by frozen section analysis of the nodules. He underwent a partial hepatectomy (S5/S8) and partial resection of the diaphragm. Pathological examination showed that the liver tumor was a foreign body granuloma that included silk suture material.DiscussionAlthough postoperative PET/CT surveillance is useful following malignant tumor resection, it is important to note that PET/CT false-positive findings are possible. Furthermore, PET/CT cannot detect small peritoneal metastases, necessitating a thorough abdominal examination.ConclusionIn cases of malignancy, the possibility of postoperative suture granuloma should be considered. In addition, a thorough surgical examination of the abdomen should be performed in cases of suspected recurrence.     

Prospective Analysis of Accuracy of Positron Emission Tomography,Computed Tomography,and Endoscopic Ultrasonography in Staging of Adenocarcinoma of the Esophagus and the Esophagogastric Junction

Background: Exact preoperative staging of esophageal cancer is essential for accurate prognosis and selection of appropriate treatment modalities.Methods: Forty-two patients with adenocarcinoma of the esophagus or the esophagogastric junction suitable for radical esophageal resection were staged with positron emission tomography (PET), spiral computed tomography (CT), and endoscopic ultrasonography (EUS).Results: Diagnostic sensitivity for the primary tumor was 83% for PET and 67% for CT; for local peritumoral lymph node metastasis, it was 37% for PET and 89% for EUS; and for distant metastasis, it was 47% for PET and 33% for CT. Diagnostic specificity for local lymph node metastasis was 100% with PET and 54% with EUS, and for distant metastasis, it was 89% for PET and 96% for CT. Accuracy for locoregional lymph node metastasis was 63% for PET, 66% for CT, and 75% for EUS, and for distant metastasis, it was 74% with PET and 74% with CT. Of the 10 patients who were considered inoperable during surgery, PET identified 7 and CT 4. The false-negative diagnoses of stage IV disease in PET were peritoneal carcinomatosis in two patients, abdominal para-aortic cancer growth in one, metastatic lymph nodes by the celiac artery in four, and metastases in the pancreas in one. PET showed false-positive lymph nodes at the jugulum in three patients.Conclusions: The diagnostic value of PET in the staging of adenocarcinoma of the esophagus and the esophagogastric junction is limited because of low accuracy in staging of paratumoral and distant lymph nodes. PET does, however, seem to detect organ metastases better than CT.     

Impact of <Superscript>18</Superscript>F-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography (FDG-PET) in Patients with Biochemical Evidence of Recurrent or Residual Medullary Thyroid Cancer

Background: Conventional imaging such as with ^99mTc(V)dimercaptosunnic acid (DMSA), ¹¹¹In-octreotide scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) rarely localizes occult medullary thyroid cancer (MTC). The role of ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is not well defined. The aim of this study was to examine the usefulness of postoperative FDG-PET in localizing MTC metastases.Methods: FDG-PET was performed in 26 patients with elevated serum tumor markers after total thyroidectomy with central compartment dissection and additional neck dissection on indication. Patient- and lesion-based results were compared with the findings of conventional nuclear imaging and validated by morphological imaging (CT, MRI, ultrasonography), including bone scintigraphy and pathology when possible. Clinical impact was evaluated.Results: FDG-PET detected foci in 50% of patients with lesion-based sensitivity of 96%. ¹¹¹In-octreotide detected foci in 19% with sensitivity of 41%, and ^99mTc(V)DMSA scintigraphy and morphological imaging detected foci in 21% and 40%, respectively, with sensitivity of 57% and 87%. No lesions were found in 11 patients (42%). Positive FDG-PET findings led to surgical intervention in nine patients (35%). They all underwent surgery for removal of residual tumor or metastases. One patient achieved disease-free status. In all patients who underwent surgery, serum calcitonin levels were reduced by an average of 58 ± 31%.Conclusions: For detection of occult MTC lesions, FDG-PET is superior to conventional nuclear imaging and is the best detection method yet available. FDG-PET in postoperative follow-up has clinical value and may be used for guiding reoperation and additional morphological imaging preoperatively.     

Comparison of preoperative whole-body positron emission tomography with MDCT in patients with primary colorectal cancer

Objective  Preoperative use of emission tomography with¹⁸F-fluorodeoxyglucose (FDG-PET) in patients with primary colorectal cancer remains controversial. This study evaluated the additional value of FDG-PET in comparison with routine multidetector row computed tomography (MDCT) in patients with primary colorectal cancer.
Method  Retrospective analysis was performed in 65 patients with colorectal cancer who underwent whole-body FDG-PET. Results of FDG-PET were compared with routine preoperative evaluation by MDCT regarding detection of primary tumour, lymph node involvement and distant metastases. All images were evaluated before surgery.
Results  Tumour detection rate was 100% (63/63) for MDCT and 98% (62/63) for FDG-PET. Lymph node involvement was pathologically confirmed in 35 patients. MDCT and FDG-PET displayed sensitivities of 89% (31/35; 95% CI: 73–97%) and 43% (15/35; 95% CI: 26–61%) and specificities of 52% (11/21; 95% CI: 30–74%) and 95% (20/21; 95% CI: 76–100%), respectively. Liver metastases were present in 22 patients. MDCT and FDG-PET showed accuracies of 98% (64/65; 95% CI: 92–100%) and 97% (63/65; 95% CI: 89–100%), respectively. FDG-PET detected additional extrahepatic metastatic lesions and affected treatment plan compared with MDCT in 10 patients.
Conclusion  Preoperative FDG-PET is not superior to MDCT for detection of primary tumour, lymph node involvement or liver metastases, but may have potential clinical value in patients with advanced colorectal cancer by detecting extrahepatic distant metastases.     

18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is accurate for high-grade prostate cancer bone staging when compared to bone scintigraphy

IntroductionIn this study, we compared ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-positron emission tomography/computed tomography (PET/CT) and bone scintigraphy accuracies for the detection of bone metastases for primary staging in high-grade prostate cancer (PCa) patients to determine if ¹⁸F-FDG-PET/CT could be used alone as a staging modality.MethodsMen with localized high-grade PCa (n=256, Gleason 8–10, International Society of Urological Pathology [ISUP] grades 4 or 5) were imaged with bone scintigraphy and ¹⁸F-FDG-PET/CT. We compared, on a per-patient basis, the accuracy of the two imaging modalities, taking inter-modality agreement as the standard of truth (SOT).Results¹⁸F-FDG-PET/CT detected at least one bone metastasis in 33 patients compared to only 26 with bone scan. Of the seven false-negative bone scintigraphies, four (57.1%) were solitary metastases (monometastatic), three (42.9%) were oligometastatic (2–4 lesions), and none were plurimetastatic (>4 lesions). Compared to SOT, ¹⁸F-FDG-PET/CT showed higher sensitivity and accuracy than bone scintigraphy (100% vs. 78.8%, and 98.7% vs. 98.2%) for the detection of skeletal lesions.Conclusions¹⁸F-FDG-PET/CT appears similar or better than conventional bone scans to assess for bone metastases in patients newly diagnosed with high-grade PCa. Since intraprostatic FDG uptake is also a biomarker for failure of radical prostatectomy and that FDG-PET/CT has been shown to be accurate in detecting PCa lymph node metastasis, FDG-PET/CT has the potential to be used as the sole preoperative staging modality in high-grade PCa.     

正电子发射型断层显像在结直肠癌肝转移诊断中的应用

目的 评价正电子发射型断层显像(PET)在结直肠癌术后肝转移诊断中的作用。方法 对18例怀疑结直肠癌术后肝转移的患者和3例怀疑其他疾病的患者进行PET检查，通过与CT比较及手术探查，评价PET在结直肠癌肝转移诊断中的作用。结果 怀疑术后肝转移的18例患者，经PET显像确诊17例，其中14例同时伴有肝脏以外的其他脏器转移(肺转移2例、腹壁转移2例、骨转移1例、腹腔淋巴结转移6例、纵隔淋巴结转移2例、锁骨上淋巴结转移1例)；PET诊断阴性的1例患者，随访1年后仍无瘤存活。3例怀疑其他疾病的患者经PET检查发现有结肠癌伴肝转移。结论 与CT相比，PET对结直肠癌术后肝脏及其他部位转移的敏感度更高，对术后肝转移患者是否选择再次手术具有更好的指导意义。