Impact of F18-fluorodeoxyglycose positron emission tomography/computed tomography on the management of resectable pancreatic tumours

Background: Positron emission tomography/computed tomography (PET/CT) using F18‐fluorodeoxyglucose has been shown to be valuable in the management of malignant disease. The aim of this study is to investigate the impact of this technique on the management of patients with resectable pancreatic tumours. Methods: Thirty‐six patients with 37 potentially resectable pancreatic tumours on diagnostic CT imaging underwent PET/CT scans. Operative findings, histological reports and/or clinical follow‐up served as standard of reference. The impact of PET/CT on patient management was estimated by calculating the percentage of patients whose treatment plan was altered due to PET/CT. Results: Pancreatic adenocarcinoma was diagnosed in 30 patients, neuroendocrine tumours in 3, mass‐forming pancreatitis in 3 and serous cystadenoma in 1. The median standard uptake (max) value was 5.0 (range 2.2–12.0). Sensitivity and specificity of detecting extrapancreatic metastatic disease were 73% and 100%, respectively. Three occult liver metastases were detected at laparotomy following negative PET/CT. PET/CT findings influenced the management of 8 (22%) patients – 3 with liver metastases, 3 with bone metastases, 1 with lymph node metastases and 1 by identifying the benign appearance of the pancreatic tumour. Conclusion: PET/CT achieves a significant diagnostic impact in detecting extrapancreatic metastatic disease. F18‐fluorodeoxyglucose PET/CT appears to be useful in assessing suspicious pancreatic masses.     

Clinical use of fluorodeoxyglucose F 18 positron emission tomography for detection of renal cell carcinoma

PURPOSE: We evaluate the role of fluorodeoxyglucose F 18 positron emission tomography (PET) in patients with renal cell carcinoma (RCC) by retrospective review. To our knowledge this series is the largest reviewing the use of PET in patients with RCC. MATERIALS AND METHODS: A total of 66 patients who underwent 90 PET scans for suspected or known RCC were identified. Dictated reports of PET, chest computerized tomography (CT), abdominal/pelvic CT and bone scan were examined with confirmation of results by histopathology or followup of at least 1 year. The accuracies of PET and conventional imaging modalities were compared. RESULTS: PET exhibited a sensitivity of 60% and specificity of 100% for primary RCC tumors (abdominal CT demonstrated 91.7% sensitivity and 100% specificity). For retroperitoneal lymph node metastases and/or renal bed recurrence, PET was 75.0% sensitive and 100.0% specific (92.6% sensitivity and 98.1% specificity for abdominal CT). PET had a sensitivity of 75.0% and a specificity of 97.1% for metastases to the lung parenchyma compared to 91.1% and 73.1%, respectively, for chest CT. PET had a sensitivity of 77.3% and specificity of 100.0% for bone metastases, compared to 93.8% and 87.2% for combined CT and bone scan. In 39 scans (32 patients) PET failed to detect RCC lesions identified by conventional imaging. CONCLUSIONS: The role of fluorodeoxyglucose F 18 PET in the detection of RCC is limited by low sensitivity. With superior specificity PET may have a complementary role as a problem solving tool in cases that are equivocal on conventional imaging.     

Contribution of 18F-fluorodeoxyglucose positron emission tomography to the diagnosis of early pancreatic carcinoma

Background/Purpose  Pancreatic carcinoma has a poor prognosis, and early detection is essential to allow potentially curative resection. Despite the wide array of diagnostic tools available, the detection of small pancreatic tumors remains difficult. The aim of this study was to investigate the contribution of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) to the diagnosis of early pancreatic cancer. Methods  FDG-PET was performed in 56 patients with pancreatic cancer who underwent curative surgery. The standardized uptake value (SUV) for FDG was calculated in each patient and the relationships between the SUV and various clinicopathological factors were analyzed. Results  The tumors ranged from 0.8 to 6.5 cm in diameter. When the cutoff value for the SUV was set at 2.5, 51 of the 56 patients (91%) had a positive FDG-PET study. The SUV did not show a significant difference in relation to tumor differentiation or pTS and pT factors. There was also no correlation between the SUV and the maximum tumor diameter (r = 0.22; P = 0.1). Five tumors had an SUV below the cutoff value, and all of these lesions had intermediate or scirrhous stroma rather than medullary stroma. Conclusions  These results indicate that FDG-PET is useful for the detection of small early pancreatic cancers.     

High-resolution fluorodeoxyglucose positron emission tomography with compression ("positron emission mammography") is highly accurate in depicting primary breast cancer

We sought to prospectively assess the diagnostic performance of a high-resolution positron emission tomography (PET) scanner using mild breast compression (positron emission mammography [PEM]). Data were collected on concomitant medical conditions to assess potential confounding factors. At four centers, 94 consecutive women with known breast cancer or suspicious breast lesions received 18F-fluorodeoxyglucose (FDG) intravenously, followed by PEM scans. Readers were provided clinical histories and x-ray mammograms (when available). After excluding inevaluable cases and two cases of lymphoma, PEM readings were correlated with histopathology for 92 lesions in 77 women: 77 index lesions (42 malignant), 3 ipsilateral lesions (3 malignant), and 12 contralateral lesions (3 malignant). Of 48 cancers, 16 (33%) were clinically evident; 11 (23%) were ductal carcinoma in situ (DCIS), and 37 (77%) were invasive (30 ductal, 4 lobular, and 3 mixed; median size 21 mm). PEM depicted 10 of 11 (91%) DCIS and 33 of 37 (89%) invasive cancers. PEM was positive in 1 of 2 T1a tumors, 4 of 6 T1b tumors, 7 of 7 T1c tumors, and 4 of 4 cases where tumor size was not available (e.g., no surgical follow-up). PEM sensitivity for detecting cancer was 90%, specificity 86%, positive predictive value (PPV) 88%, negative predictive value (NPV) 88%, accuracy 88%, and area under the receiver-operating characteristic curve (Az) 0.918. In three patients, cancer foci were identified only on PEM, significantly changing patient management. Excluding eight diabetic subjects and eight subjects whose lesions were characterized as clearly benign with conventional imaging, PEM sensitivity was 91%, specificity 93%, PPV 95%, NPV 88%, accuracy 92%, and Az 0.949 when interpreted with mammographic and clinical findings. FDG PEM has high diagnostic accuracy for breast lesions, including DCIS.     

Positron emission tomography in the study of cerebral tumours

Summary Positron emission tomography (PET) uses the shortlived positron-emitting radioisotopes of elements such as oxygen, nitrogen, and carbon as tracers both to image and to measure, non-invasively, normal regional tissue physiology and pathophysiology in man. This technique has been used to study the pathophysiology of brain tumours at the time they present and after therapeutic intervention.     

18-fluorodeoxyglucose positron emission tomography in predicting survival of patients with pancreatic carcinoma

The prediction of survival of patients with pancreatic cancer is usually based on tumor staging and grading and on the level of tumor markers. However, accurate tumor staging can be obtained only after resection, and still there is a great difference in survival rates among patients with the same clinicopathologic parameters. Recently the uptake of 18-fluorodeoxyglucose (FDG) by positron emission tomography (PET) has been found to be correlated with survival in patients with pancreatic cancer. This study evaluated the role of ¹⁸FDG PET as a prognostic factor for patients with pancreatic cancer. From June 1996 to July 2002, a total of 118 patients underwent PET for pancreatic cancer. The standardized uptake value (SUV) of ¹⁸FDG was calculated in 60 of them, and these patients were divided into high (>4) and low (≦4) SUV groups. They were also evaluated according to the tumor node metastasis (TNM) classification system of the International Union Against Cancer, and by tumor grade, medical or surgical treatment, diabetes, age, sex, and CA19-9 serum levels. Twenty-nine cancers showed high and 31 showed low SUVs. Survival was significantly influenced by tumor stage (P = 0.0001), tumor grade (P = 0.01), and SUV (P = 0.005). Multivariate analysis showed that only stage (P = 0.001) and SUV (P = 0.0002)were independent predictors of survival. When patients who were analyzed for SUV were stratified according to the other variables, FDG uptake was related to survival also after stratification for the following: stage III to IVa (P = 0.002), stage IVb (P = 0.01), tumor resection (P = 0.006), moderately differentiated tumors (P = 0.01), age less than 65 years (P = 0.006), CA 19–9 levels greater than 300 kU/L (P = 0.002), and absence of diabetes (P = 0.0001). The SUV calculated with ¹⁸FDG PET is an important prognostic factor for patients with pancreatic cancer and may be useful in selecting patients for therapeutic management. Presented at the Forty-Fourth Annual Meeting of The Society for Surgery of the Alimentary Tract, Orlando, Florida, May 17–22, 2003 (oral presentation); and the Sixth National Congress of the Italian Association of Nuclear Medicine, Genoa, Italy, November 15–19, 2002.     

The role of positron emission tomography in the management of colorectal cancer

Positron emission tomography (PET) is a functional imaging modality that has made the transition from the research enviroment to the clinical enviroment over the last 10 years. Its major role is in the field of oncology where it is being used increasingly in the management of several tumour types including colorectal cancer. This review aims to outline the current and future role of PET scanning in the field of colorectal cancer.     

Significance of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for detection of renal cell carcinoma and immunohistochemical glucose transporter 1 (GLUT-1) expression in the cancer

OBJECTIVE: Positron emission tomography (PET) is now primarily used in oncological indication owing to the successful application of fluorine-18 fluorodeoxyglucose (FDG) in an increasing number of clinical indications. Glucose transporter 1 (GLUT-1) is recognized as a major early marker of cellular malignant transformation. The aims of this study were to assess whether FDG-PET is a useful diagnostic tool for renal cell carcinoma and to compare the pathologic characteristics. METHODS: Nineteen consecutive patients who had renal cell carcinoma were examined using FDG-PET preoperatively. The results of PET were then compared to the histology obtained after radical surgery and the immunoreactivity of GLUT-1 was also studied. RESULTS: Pathologic examination confirmed that all 19 patients suffered from renal cell carcinoma. Increased FDG uptake was found in six of the 19 patients (31.5%). The immunohistochemical examination of GLUT-1 in renal cell carcinoma produced different results in each patient. There was no correlation with GLUT-1 immunoreactivity and FDG-PET positivity. CONCLUSION: These results suggest that FDG-PET may not be a useful diagnostic tool for renal cell carcinoma.     

Value of fluorodeoxyglucose positron emission tomography in characterizing clinically‐significant thyroid carcinomas

Background: Despite the rising incidence of thyroid incidentalomas, their clinical significance remains unclear. The present study aimed to determine whether fluorodeoxyglucose positron emission tomography (FDG‐PET) is associated with a significantly higher risk of clinically‐significant thyroid carcinoma (CSC) in incidentalomas than other non‐functional imaging modalities. Methods: Over a 2‐year period, 89 patients were identified as having a thyroid incidentaloma. All patients had either surgery or fine needle aspiration cytology (FNAC) with a 12‐month follow up to confirm the nature of the incidentaloma. Surgery was carried out for nodules with malignant or indeterminate FNAC result, or those with in a retrosternal location, with size > 4 cm or local symptoms. Results: A total of 21 (23.6%) patients had their incidentaloma detected by FDG‐PET (PET group) and 68 (76.4%) by non‐PET imaging modalities (non‐PET group). Differentiated thyroid carcinoma was confirmed in 18 (20.2%) patients. The rate of malignancy was 61.9% in the PET group and 7.4% in the non‐PET group (P = 0.001). After excluding the occult microcarcinomas, the risk of malignancy reduced to 14.6%, but the difference in malignancy rate became more marked between the PET and non‐PET group (42.9% vs 2.9%, P = 0.001). The maximum standardized uptake value on FDG‐PET was similar between benign and malignant lesions (P = 0.124). Conclusion: The overall risk of CSC in thyroid incidentalomas was 14.6%. Those detected by FDG‐PET were significantly more likely to harbour CSC than those by non‐functional modalities. Incidentalomas with focal FDG uptake should be thoroughly investigated with USG and FNAC.     

Diagnosis of renal and hepatic cyst infections by 18-F-fluorodeoxyglucose positron emission tomography in autosomal dominant polycystic kidney disease

Background:Infection of a renal or hepatic cyst is a serious complication of autosomal dominant polycystic kidney disease (ADPKD). Although crucial for successful management, early diagnosis is difficult, largely because of nonspecific symptoms and limitations of conventional imaging techniques. Because of an increased metabolic rate, inflammatory cells take up large amounts of glucose. 18-F-fluorodeoxyglucose (FDG), therefore, represents a promising agent for detection of cyst infections using positron emission tomography (PET).Methods:The authors studied the results of 7 FDG PET scans in 3 ADPKD patients suspected of renal or hepatic cyst infection. Two PET scans were performed in patient A (PET 1 and 2), one PET scan was performed in patient B (PET 3), and 4 PET scans were performed in patient C (PET 4, 5, 6 and 7).Results:FDG PET identified the infected cysts in 2 episodes of renal cyst infection (PET 2 and 3), 2 episodes of hepatic cyst infection (PET 6 and 7), and 1 episode of both renal and hepatic cyst infection (PET 1). In patient C, FDG PET was normal after 6 weeks of antibiotic treatment for hepatic cyst infection (PET 4) and again at a time when hepatic cyst infection was suspected, but eventually colchicine intoxication was diagnosed (PET 5).Conclusion:In these patients, FDG PET proved very helpful in diagnosing and in excluding renal and hepatic cyst infections. It is concluded that FDG PET is a promising new imaging technique enabling early identification of renal and hepatic cyst infections in ADPKD patients.     

The influence of 18F-fluorodeoxyglucose positron emission tomography/computed tomography on the N- and M-staging and subsequent clinical management of intrahepatic cholangiocarcinoma

BackgroundIntrahepatic cholangiocarcinoma (ICC) is a highly metastatic cancer. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) enables sensitive tumor and metastasis detection. Our aim is to evaluate the influence of pre-treatment PET/CT on the N- and M-staging and subsequent clinical management in ICC patients.MethodsBetween August 2010 and August 2018, 660 consecutive ICC patients, without prior anti-tumor treatments nor other malignancies, were enrolled. The diagnostic performance of PET/CT on the N- and M-staging was compared with conventional imaging, and the preoperative staging accuracy and treatment re-allocation by PET/CT were retrospectively calculated. Survival difference was compared between patients receiving PET/CT or not after propensity score matching.ResultsPatients were divided into group A (n=291) and group B (n=369) according to whether PET/CT was performed. Among 291 patients with both PET/CT and conventional imaging for staging in group A, PET/CT showed significantly higher sensitivity (83.0% vs. 70.5%, P=0.001), specificity (88.3% vs. 74.9%, P<0.001) and accuracy (86.3% vs. 73.2%, P<0.001) than conventional imaging in diagnosing regional lymph node metastasis, as well as higher sensitivity (87.8% vs. 67.6%, P<0.001) and accuracy (93.5% vs. 89.3%, P=0.023) in diagnosing distant metastasis. Overall, PET/CT improved the accuracy of preoperative staging from 60.1% to 71.8% (P<0.001), and modified clinical treatment strategy in 5.8% (17/291) of ICC patients, with unique roles in different tumor-node-metastasis (TNM) stages. High tumor-to-non-tumor ratio (TNR) predicted poor overall survival [hazard ratio (HR) = 2.17; 95% confidence interval (CI): 1.49–3.15; P<0.001]. Furthermore, patients performing PET/CT had longer overall survival compared with those without PET/CT (HR =0.74; 95% CI: 0.58–0.93; P=0.011) after propensity score matching.ConclusionsPET/CT was valuable for diagnosing regional lymph node metastasis and distant metastasis in ICC patients, and facilitated accurate tumor staging and optimal treatment allocation.     

The use of positron emission tomography in detecting hepatoblastoma recurrence--a cautionary tale

Purpose

The use of positron emission tomography (PET) with [18F] fluorodeoxyglucose (FDG) in the detection of recurrences has been well established in many tumor types. Here the authors present their experience using this modality in the evaluation of posttreatment hepatoblastoma patients.

Methods

The authors conducted a retrospective review on patients with hepatoblastoma diagnosed from 1996 to 2003. FDG-PET imaging was performed together with measurement of alpha-fetal protein (AFP) during posttreatment follow-up.

Results

Sixteen patients (8 boys and 8 girls) were identified in this series. The mean age was 23.5 months (range, 5 months to 4 years). Three posttreatment patients had PET results suggestive of tumor recurrence. One of these patients had normal AFP level and suspected recurrence in the caudate lobe. Radiologic-guided biopsy was performed 3 times, and there was no evidence of tumor. The other 2 patients underwent further liver resections because of mildly raised AFP levels. The histology of these showed regenerative liver tissue only with no hepatoblastoma recurrence.

Conclusions

Although PET has been gaining popularity as a tool in the detection of tumor recurrences worldwide, it has been shown in this series that PET may not be useful in hepatoblastoma patients, and caution must be taken in the interpretation of positive results.     

Multilocular cystic renal cell carcinoma: clinicopathological features and preoperative prediction using multiphase computed tomography

Study Type – Diagnostic (exploratory cohort) Level of Evidence 2b What’s known on the subject? and What does the study add? Multilocular cystic renal cell carcinoma (MCRCC), defined according to the 2004 WHO classification, has good prognosis, which is not affected adversely by large tumour size or advanced stage. Thus nephron‐sparing surgery is proposed when MCRCC is suspected by preoperative radiologic criteria. The present study confirms the low malignant potential of MCRCC. Additionally, the results of the present study provide a simple, useful criteria using a Bosniak classification and Hounsfield unit on multiphase computed tomography images to differentiate MCRCC from other cystic RCC.

OBJECTIVE

? To analyse the clinicopathological and radiological features of multilocular cystic renal cell carcinoma (MCRCC) and to determine the preoperative factors differentiating MCRCC from other cystic RCC (CRCC).

PATIENTS AND METHODS

? The medical records of 53 patients with complex cystic renal masses evaluated by multiphase computed tomography (CT), surgically removed and confirmed as sporadic RCC were reviewed. ? Of these 53 patients, 23 were classified as having MCRCC and 30 as other CRCCs, defined as RCCs with extensive cystic change or cystic necrosis. ? Another 22 patients were treated for complex cystic renal masses presumed to be RCC and diagnosed as having benign cyst.

RESULTS

? Benign cysts and MCRCCs were significantly more likely to be of Bosniak classification III than other CRCCs (77% vs 61% vs 27%, P= 0.001). ? The mean Hounsfield unit (HU) during the corticomedullary phase (CMP) was significantly higher in other CRCCs, with HU ≥38 having 83% sensitivity and 80% specificity for predicting other CRCCs. ? In a multiple regression model, Bosniak classification and mean HU during CMP were independent factors predictive of other CRCCs. ? In the 41 patients with masses >4 cm in diameter, the combination of Bosniak classification IV and HU ≥38 during CMP showed 63% sensitivity, 96% specificity, 91% positive predictive value and 80% negative predictive value, yielding 2% false‐positive and 15% false‐negative rates.

CONCLUSIONS

? The mean HU during CMP and Bosniak classification can differentiate MCRCC from other CRCCs. ? This could help in selecting an appropriate surgical method, such as nephron‐sparing surgery, for complex cystic renal masses >4 cm.