Positron emission tomography in lung cancer

Recent advances in positron emission tomography (PET) with 2-deoxy-2-fluoro [F-18]-d-glucose (FDG) has enabled not only the diagnosis and staging of lung cancer but also the prediction of its malignancy grade. However, FDG-PET has been known to have several pitfalls for imaging of lung cancer. For the effective clinical use of FDG-PET in lung cancer, we reviewed the pitfalls of using FDG-PET in the diagnosis of pulmonary nodules, semiquantitative analysis of FDG-uptake, N-staging, prediction of tumor aggressiveness, prognostic significance, and prediction of pathological response after chemoradiotherapy. __________ This review was submitted at the invitation of the editorial committee.     

PET/CT诊断乳腺癌及腋窝淋巴结状态的作用评价

目的：评价PET／CT诊断乳腺癌和腋窝淋巴结转移的临床价值。方法：对33例疑似乳腺癌病人进行PET／CT检查，定性分析肿瘤病灶、淋巴结摄取氟脱氧葡萄糖（FDG）的程度，半定量测量标准摄取值（SUV），根据乳腺和淋巴结的FDG摄取强度诊断乳腺癌和淋巴结转移，检验SUV与乳腺癌分化程度、有丝分裂计数的关联性。结果：PET／CT诊断乳腺癌和腋窝淋巴结转移的敏感度、特异度和精确度分别为92．6％、100％、93．9％和82．3％、90％、85．2％；SUV与乳腺癌分化程度、有丝分裂计数显著相关（P〈0．05）；诊断乳腺癌的Kappa指数=0．835，μ=8．48，（P〈0．01）。结论：PET／CT诊断乳腺癌和腋窝淋巴结转移的敏感度、特异度较高，作为一种非侵袭性检查方法，可提供乳腺癌在活体内的多方面生物学信息，为选择合理的手术方式及新辅助化疗提供参考，弥补传统检查方法的不足。     

Positron emission tomography in a patient with renal malacoplakia

Positron emission tomography is increasingly used for the diagnosis of occult infection or malignancy. The altered metabolic rate of cells in areas of malignancy or infection provides a sensitive method to identify pathology that is otherwise not identified by standard imaging methods. This case report describes a patient who presented with a pyrexia of unknown origin and renal impairment. She had a positron emission tomography scan that showed intense accumulation of fluoro-deoxy-glucose in both kidneys. Subsequent renal biopsy results showed a diagnosis of malacoplakia, the treatment of which resulted in a resolution of the fever and a stabilization of renal function. This is the first report of the positron emission tomographic appearance of renal malacoplakia.     

Role of fluorine-flurodeoxyglucose positron emission tomography/computed tomography in preoperative assessment of anterior mediastinal masses

Objective: The purpose of the study was to explore the usefulness of fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET-CT) in the preoperative assessment of isolated anterior mediastinal lesions, especially in the planning of operative strategy (biopsy or upfront resection). Methods: During the last 36 months, 19 consecutive patients (10 males, mean age 54 ± 16 years) underwent PET-CT in the preoperative work-up of isolated anterior mediastinal diseases. Maximal transverse diameter at CT and the postoperative histology and Masaoka staging for thymomas were collected and related to the maximum standardised uptake values (SUVs). Thymomas were divided into low-risk thymoma (LRT = A, AB and B1) and high-risk thymoma (HRT = B2, B3 and C). Results: There were 13 thymomas (six LRT and seven HRT), three lymphomas and three other primitive thymic tumours (one paraganglioma, two non-seminomatous germ cell tumours). In LRT, the mean SUV was 3.3 ± 0.5 resulting significantly lower than HRT, 13.5 ± 7 (p = 0.009). The SUV in LRT was also significantly lower with respect to lymphoma, 12.4 ± 4 (p = 0.001), and the other primitive anterior mediastinal tumours, 8 ± 0.8 (p = 0.001). Between thymomas we found a significant correlation between Masaoka stage and SUV, r = 0.718, p = 0.006. No correlation was found between transverse diameters and SUV, r = 0.141, p = 0.6. Conclusions: In our experience, low SUV (<5) is associated with LRT and minimal invasive thymoma (Masaoka stages I–II) and, therefore, susceptible to upfront surgery. For lesions with an infiltrative aspect on CT scan associated with a higher SUV (>5), an open biopsy is mandatory to exclude mediastinal lymphomas or, in case of HRT, to address a neoadjuvant treatment.     

Positron emission tomography with F-18-fluorodeoxyglucose in a combined staging strategy of esophageal cancer prevents unnecessary surgical explorations

Distant metastases or local invasion are frequently found during the explorative phase of surgery for esophageal cancer. This study was performed to determine the rate of patients with incurable disease encountered during exploration and to examine the impact of preoperative staging, including positron emission tomography (PET), on the number of unnecessary explorations. The records of 203 patients with esophageal cancer who were eligible for curative resection were retrospectively reviewed. The surgical reports were analyzed to obtain the reasons for abandoning resection. Furthermore, the different staging modalities according to the related time interval were reviewed for each patient to analyze the influence of them on the number of explorations. After exploratory surgery, resection was abandoned in 78 of the 203 patients (38%) because of distant metastases (n = 59; 29%), metastatic spread and local irresectability (n = 5; 2%), and local irresectability (n = 14; 7%). In a logistic regression model with all preoperative staging modalities and the year of examination as independent variables, F-18-fluorodeoxyglucose (FDG)-PET) was the only modality that predicts intended curative resection in these patients (P < 0.001). In patients with esophageal cancer who are suitable for potentially curative surgery, resection was abandoned mainly because of distant metastases encountered during exploration. The addition of FDG-PET may have reduced the rate of unnecessary surgery in this group of patients. Presented at the Forty-Fifth Annual Meeting of The Society for Surgery of the Alimentary Tract, New Orleans, Louisiana, May 15–19, 2004 (poster presentation).     

Clinical significance of incidental findings on staging positron emission tomography for oesophagogastric malignancies

Introduction

The aim of this retrospective study was to determine the clinical significance of incidental findings detected on positron emission tomography (PET) in patients undergoing staging of oesophagogastric malignancies.

Methods

Patients with oesophagogastric malignancies who underwent PET between June 2007 and May 2012 were included in the study. PET was performed according to hospital protocol. All imaging was interpreted by two consultant radiologists in nuclear medicine. Incidental findings that were unrelated to the primary malignancy were recorded and patients were recommended to have further investigations (imaging, endoscopy and biopsy).

Results

Overall, 333 patients (240 male, 93 female; mean age: 67 years) with upper gastrointestinal malignancies were eligible for inclusion in the study. Eighty-nine of these patients had PET demonstrating one or more incidental findings. Two patients were found to have a second primary malignancy. One patient had a distant metastasis of his primary cancer and six patients had a premalignant lesion.

Conclusions

In this study, incidental findings were discovered in 26.7% of patients with known oesophagogastric cancer. A second primary cancer or premalignant lesion was found in 8.4% of patients with incidental findings. Patients with these findings should be investigated to rule out further malignancy. There were a high proportion of false positive results in our study. It is recommended that each patient is considered on an individual basis and assessed with simultaneous PET and computed tomography.     

Positron emission mammography: initial clinical results

Background: Evaluation of high-risk mammograms represents an enormous clinical challenge. Functional breast imaging coupled with mammography (positron emission mammography [PEM]) could improve imaging of such lesions. A prospective study was performed using PEM in women scheduled for stereotactic breast biopsy.Methods: Patients were recruited from the surgical clinic. Patients were injected with 10 mCi of 2-[¹⁸F] fluorodeoxyglucose. One hour later, patients were positioned on the stereotactic biopsy table, imaged with a PEM scanner, and a stereotactic biopsy was performed. Imaging was reviewed and compared with pathologic results.Results: There were 18 lesions in 16 patients. PEM images were analyzed by drawing a region of interest at the biopsy site and comparing the count density in the region of interest with the background. A lesion-to-background ratio >2.5 appeared to be a robust indicator of malignancy and yielded a sensitivity of 86%, specificity of 91%, and overall diagnostic accuracy of 89%. No adverse events were associated with the PEM imaging.Conclusions: The data show that PEM is safe, feasible, and has an encouraging accuracy rate in this initial experience. Lesion-to-background ratios >2.5 were found to be a useful threshold value for identifying positive (malignant) results. This study supports the further development of PEM.Presented at the Society of Surgical Oncology meeting, Denver, CO, March 15–17, 2002     

Results of computerized tomography guided percutaneous ablation of renal masses with nondiagnostic pre-ablation pathological findings

PURPOSE: Ablative therapy for renal masses has been criticized because the entire tumor cannot be evaluated pathologically after the procedure. Diagnosis depends on imaging findings and the results of percutaneous needle biopsies, which may be nondiagnostic in up to 21% of cases. We determined outcomes in patients undergoing ablation who had nondiagnostic biopsies at the time of the procedure. MATERIALS AND METHODS: A total of 79 patients (88 renal masses) underwent percutaneous computerized tomography guided biopsy and ablation of a renal mass under conscious sedation. Patients with nondiagnostic biopsies were identified and the medical records were reviewed retrospectively. All patients had an enhancing renal mass on preoperative computerized tomography or magnetic resonance imaging and all underwent postoperative contrast imaging to evaluate persistent viable tumor. RESULTS: A total of 19 patients (20 tumors) with nondiagnostic percutaneous biopsy (22.7% or 20 of 88) were included in the study. No serious complications occurred. Tumors were treated with frequency ablation (12) or cryoablation (7). In 17 patients (89.5%) post-procedure imaging confirmed the absence of contrast enhancement at a median followup of 27.3 months (range 3 weeks to 56 months). In 2 cases (10.5%) post-procedure imaging showed a residual renal mass or recurrence with enhancement, suggesting that the original percutaneous biopsy result was false negative. In 1 patient residual tumor was identified on initial post-ablation imaging and the patient underwent laparoscopic partial nephrectomy. In another patient recurrence was diagnosed 30 months after ablation and the patient underwent laparoscopic radical nephrectomy. Although there was a nondiagnostic percutaneous biopsy in each case, pathological findings in the subsequent surgical specimen confirmed renal cell carcinoma. CONCLUSIONS: Nondiagnostic percutaneous biopsy at renal tumor ablation does not obviate the need for standard post-procedure imaging followup. Of patients with nondiagnostic biopsies in this series 10.5% still harbored viable renal cell carcinoma after percutaneous ablation.     

The use of 18F-FDG positron emission tomography to detect mediastinal lymph nodes in metastatic breast cancer

BackgroundTo assess the predictive value of ¹⁸F-fluorodeoxyglucose positron-emission tomography (FDG–PET/CT) in detecting mediastinal lymph node metastasis with histopathologic verification in breast cancer (BC) patients.Materials and methodsBetween February 2012 and October 2019, 37 BC patients who underwent histopathological verification for FDG-PET positive mediastinal lymph nodes were retrospectively analyzed. Nine patients (24%) were screened before beginning treatment, while 27 (76%) were screened at the time of disease progression, an average of 39 months after completion of initial treatment.ResultsThe histopathologic diagnosis revealed lymph node metastasis from BC in 15 patients (40%) and benign disease in 22 patients (60%). The standardized uptake value (SUV_max) of mediastinal lymph nodes was significantly higher in patients with lymph node metastasis compared to those with benign histology (9.0 ± 3.5 vs. 5.9 ± 2.4; P = 0.007). The cut-off value of SUV_max after the ROC curve analysis for pathological lymph node metastasis was 6.4. Two of the 15 patients with mediastinal SUV_max ≤ 6.4 and 13 of the 22 patients with SUV_max > 6.4 had lymph node metastasis. Age and pathological findings were prognostic factors for overall survival in univariate analysis. The treatment decision was changed in 19 patients (51%) after mediastinoscopic evaluation of the entire cohort.ConclusionsThis is the first study to support the need for pathologic confirmation of a positive PET/CT result following evaluation of mediastinal lymph nodes for staging BC, either at initial diagnosis or at the time of progression. Treatment decisions were consequently altered for nearly half of the patients.     

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.     

Brain tumor imaging with synthesized f-fluorophenylalanine and positron emission tomography

Two patients with cerebral gliomas were studied with ¹⁸F-fluorophenylalanine, newly synthesized by the electrophilic substitution reaction, using positron emission tomography. The tracer accumulated markedly in the tumor lesion and delineated the extent of the lesion. This new tracer will be promising in the diagnosis of gliomas.     

特殊示踪剂正电子发射体层显像在肺部病变诊断中的应用

目的 探讨胆碱、甲硫氨酸、脱氧胸腺嘧啶核苷、乙酸盐为示踪剂的正电子发射体层显像(PET)在肺部病变诊断中的应用价值.方法 2002年6月至2007年6月对100例肺部占位病变的患者行PET检查.其中~(11)C-胆碱(CH)-PET检查58例,~(11)C-甲硫氨酸(MET)-PET检查16例,~(18)F-脱氧胸腺嘧啶核苷(FLT)-PET检查22例,~(11)C-乙酸盐(AC)-PET检查4例.结果 采用目测法判读,半定量分析法测量病变标准摄取值,结果与病理诊断及随访结果对照.结果CH-PET定性诊断灵敏度、特异度、符合率分别为84.2%(32/38)、57.9%(11/19)、75.4%(43/57).MET-PET定性诊断灵敏度、特异度、符合率分别为6/7、6/9、75.0%(12/16).FLT-PET检查定性诊断灵敏度、特异度、符合率分别为85.7%(12/14)、2/8、63.6%(14/22).CH.PET、MET-PET及FLT-PET中肿瘤标准摄取值与肿瘤大小、患者年龄不相关.AC.PET检查仅1例透明细胞癌肺转移显影,2例鳞状细胞癌、1例腺癌没有显影.结论 这些示踪剂PET对肺部病变的定性诊断有帮助,但存在假阳性和假阴性结果.     

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。     

Positron emission tomography with 68-Ga-EDTA and computed tomography in patients with subarachnoid haemorrhage

Summary 26 patients with subarachnoid haemorrhage (SAH) were investigated with 68-Ga-EDTA and positron emission tomography (PET) in order to evaluate the presence of a blood brain barrier (BBB) disturbance. Only one patient showed a BBB disruption. It is suggested that increased levels of substances with higher molecular weight than 68-Ga-EDTA in the cerebrospinal fluid (CSF) are the result of a change in the metabolism of the CSF and the brain tissue caused by a SAH.     

[18F]-Fluorodeoxyglucose Positron Emission Tomography in the Diagnosis,Treatment Stratification,and Monitoring of Patients with Retroperitoneal Fibrosis: A Prospective Clinical Study

Background

The ability to distinguish malignant from benign retroperitoneal fibrosis (RPF) and to select patients who are likely to respond to steroid treatment using a noninvasive test would be a major step forward in the management of patients with RPF.

Imaging bone microdamage in vivo with positron emission tomography

Microdamage accumulation in bone is now considered a contributing cause for bone fragility in older women. However, there is still no method to detect and quantify microdamage in vivo. We have found that positron emission tomography (PET) may be useful to detect and quantify bone microdamage in vivo using a high-resolution PET scanner with [¹⁸F]NaF as the tracer. We have done several experiments using the rat ulnar loading model that demonstrate that (1) high-resolution [¹⁸F]NaF PET can detect newly created microdamage in vivo; (2) the microdamage detected in this way is co-localized with damage detected by histological and autoradiographic procedures; and (3) high-resolution [¹⁸F]NaF PET can distinguish between the effects of mechanical loading that does not produce damage and fatigue loading that creates microdamage. The high-resolution [¹⁸F]NaF PET shows promise as a non-invasive means to image bone microdamage.     

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.