Contrast-enhanced 18F-FDG PET/CT: 1-stop-shop imaging for assessing the resectability of pancreatic cancer

Comprehensive literature review of oral and intravenous contrast-enhanced PET/CT: a step forward?

The integration of diagnostic CT scans into PET/CT facilitates a comprehensive single examination, presenting potential advantages for patients seeking a thorough one-shot check-up. The introduction of iodinated contrast media during PET scanning raises theoretical concerns about potential interference with uptake quantification, due to the modification of tissue density on CT. Nevertheless, this impact appears generally insignificant for clinical use, compared to the intrinsic variability of standardized uptake values. On the other hand, with the growing indications of PET, especially 18F-FDG PET, contrast enhancement increases the diagnostic performances of the exam, and provides additional information. This improvement in performance achieved through contrast-enhanced PET/CT must be carefully evaluated considering the associated risks and side-effects stemming from the administration of iodinated contrast media. Within this article, we present a comprehensive literature review of contrast enhanced PET/CT, examining the potential impact of iodinated contrast media on quantification, additional side-effects and the pivotal clinically demonstrated benefits of an all-encompassing examination for patients. In conclusion, the clinical benefits of iodinated contrast media are mainly validated by the large diffusion in PET protocols. Contrary to positive oral contrast, which does not appear to offer any major advantage in patient management, intravenous iodine contrast media provides clinical benefits without significant artifact on images or quantification. However, studies on the benefit-risk balance for patients are still lacking.

Prediction of synchronous distant metastasis of primary pancreatic ductal adenocarcinoma using the radiomics features derived from 18F-FDG PET and MRI

AIM

To explore the potential of the joint radiomics analysis of positron-emission tomography (PET) and magnetic resonance imaging (MRI) of primary tumours for predicting the risk of synchronous distant metastasis (SDM) in patients with pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

18F-FDG PET and MRI images of PDAC patients from January 2011 to December 2020 were collected retrospectively. Patients (n=66) who received 18F-FDG PET/CT and MRI were included in a development group. Patients (n=25) scanned with hybrid PET/MRI were incorporated in an external test group. A radiomics signature was constructed using the least absolute shrinkage and selection operator algorithm to select PET-MRI radiomics features of primary PDAC tumours. A radiomics nomogram was developed by combining the radiomics signature and important clinical indicators using univariate and multivariate analysis to assess patients' metastasis risk. The nomogram was verified with the employment of an external test group.

RESULTS

Regarding the development cohort, the radiomics nomogram was found to be better for predicting the risk of distant metastasis (area under the curve [AUC]: 0.93, sensitivity: 87%, specificity: 85%) than the clinical model (AUC: 0.70, p<0.001; sensitivity:70%, specificity: 65%) and the radiomics signature (AUC: 0.89, p>0.05; sensitivity: 65%, specificity:100%). Concerning the external test cohort, the radiomics nomogram yielded an AUC of 0.85.

CONCLUSION

PET-MRI based radiomics analysis exhibited effective prediction of the risk of SDM for preoperative PDAC patients and may offer complementary information and provide hints for cancer staging.

18F-Fluorodeoxyglucose-PET-Computerized Tomography and non-Fluorodeoxyglucose PET-Computerized Tomography in Hepatobiliary and Pancreatic Malignancies

Molecular imaging with PET-computerized tomography (PET-CT) plays an important role in oncology. There is current and evolving evidence supporting the use of fluorodeoxyglucose (FDG) and non-FDG tracers in assessment patients with hepatobiliary and pancreatic cancers in various clinical scenarios. In this chapter, we discuss the advantages and limitations of FDG and non-FDG PET-CT in the management of patients with hepatobiliary and pancreatic cancers.

The value of intravenous contrast medium in PSMA PET/CT imaging in patients with biochemical recurrence of prostate cancer

PURPOSE

To investigate the added value of diagnostic abdominal contrast-enhanced computed tomography (ceCT) in Ga-68 PSMA PET/CT in prostate cancer patients with biochemical recurrence (BCR).

METHODS

Eighty-two consecutive patients (median age, 69 years; range, 45-86 years) with BCR underwent Ga-68 PSMA PET/CT with low-dose nonenhanced (ne) whole-body CT and diagnostic ceCT. Imaging results were retrospectively reviewed by two readers (R1, R2) for diagnostic certainty, local recurrence, lymph node metastasis (LNM) and bone metastasis. Interobserver agreement was assessed. Histopathology served as reference standard in 7, imaging and clinical follow-up in 65 and clinical follow-up alone in 10 patients.

RESULTS

Certain local recurrence, LNM and bone metastasis diagnoses increased substantially from ceCT (R1: 5%/18%/32%; R2: 37%/50%/82%) to nePET/CT (R1: 78%/87%/93%; R2: 81%/87%/95%) for both readers, but the difference between nePET/CT and cePET/CT (R1: 77%/96%/92%; R2: 89%/94%/96%) was marginal. Interobserver agreement was minimal with ceCT (Krippendorff's alpha: 0.04-0.26), substantial with nePET/CT (0.60-0.86) and best with cePET/CT (0.76-0.86). The areas under the receiver operating characteristic curve (AUCs) for local recurrence for R1/R2 were 0.60/0.65 for ceCT, 0.81/0.79 for nePET/CT and 0.81/0.82 for cePET/CT. AUCs for LNMs for R1/R2 were 0.67/0.77 for ceCT, 0.91/0.82 for nePET/CT and 0.92/0.87 for cePET/CT. AUCs for BMs for R1/R2 were 0.60/0.53 for ceCT, 0.93/0.84 for nePET/CT and 0.93/0.86 for cePET/CT.

CONCLUSION

Diagnostic abdominal ceCT increases the diagnostic certainty and interobserver agreement in Ga-68 PSMA PET/CT in BCR of prostate cancer. The diagnostic performance of cePET/CT is significantly better than ceCT alone but not nePET/CT.

The Value of 18F-FDG PET/CT in Diagnosing Pancreatic Lesions: Comparison With CA19-9, Enhanced CT or Enhanced MR

Objective: To investigate the value of ¹⁸F-FDG PET/CT in diagnosing pancreatic lesions, and compare it with CA19-9, contrast-enhanced CT (CECT), and contrast-enhanced MRI (CEMR). Methods: Cases of patients with suspected pancreatic lesions examined between January 1, 2011 and June 30, 2017 were retrospectively analyzed. CA19-9, CECT and CEMR within 2 weeks of PET/CT were evaluated. We compared the diagnostic efficacy of PET/CT with CA19-9, CECT and CEMR as well as combined tests. Results: A total of 467 cases were examined in this study, including 293 males and 174 females, with an average age of 57.79 ± 12.68 y (16-95 y). Cases in the malignant group (n = 248) had significantly higher SUVmax (7.34 ± 4.17 vs. 1.70 ± 2.68, P < 0.001) and CA19-9 (663.21 ± 531.98 vs. 87.80 ± 218.47, P < 0.001) than those in the benign group (n = 219). The sensitivity, specificity and accuracy of PET/CT were 91.9, 96.3, and 94.0%, respectively. Those for CECT were 83.6, 77.8, 81.2%, respectively; and 91.2, 75.0, 81.7% were for CEMR. PET/CT corrected 14.7% (28/191) CECT diagnoses and 12.2% (10/82) CEMR diagnoses. Although the diagnostic efficiency of CA19-9 was acceptable (80.0, 69.0, 74.9% respectively), the joint application of PET/CT and CA19-9 could significantly enhance the diagnostic efficiency compared with PET/CT alone (sen 97.4 vs. 90.5%, P = 0.0003; spe 100.0 vs. 95.2%, P = 0.0047). Conclusions: PET/CT has sensitivity similar to CECT, CEMR and significantly higher specificity and accuracy, helping reduce false diagnoses of morphological images. Combining PET/CT with CA19-9 could enhance diagnostic efficiency.

Complementary imaging of ultrasound and PET/CT: A new opportunity?

AIM

To evaluate the effectiveness of complementary imaging of high-resolution ultrasound including CEUS with PET/CT for tissue characterization and tumor detection.

MATERIAL AND METHODS

100 patients were examined with PET/CT and US/CEUS between January 2018 until February 2020. All patients underwent PET/CT followed by selective US/CEUS within 4 weeks. Comparison regarding concordant or diverging findings in PET/CT and US. Analysis of the differences concerning the lesions number of found by PET/CT and US/CEUS or the possibility of a secured diagnosis following ultrasound causing therapeutic changes.

RESULTS

Diverging findings regarding the number of liver lesions in PET/CT and CEUS were found in 35 out of 64 patients (54%). Regarding renal lesions, a more definite diagnosis following ultrasound, causing a change of therapeutic approach, was achieved in 89%. Concordant results in PET/CT and US were found in 83% of patients with splenic and nodal findings. In 78% of patients with increased musculoskeletal or soft tissue tracer uptake, US was able to make a secured diagnosis with therapeutic changes.

CONCLUSION

The present results indicate a strong benefit of complementary imaging of PET/CT and selective, high-resolution ultrasound especially in patients with liver, renal and musculoskeletal or soft tissue findings.

The Role of Positron Emission Tomography/Computed Tomography (PET/CT) for Staging and Disease Response Assessment in Localized and Locally Advanced Pancreatic Cancer

Pancreatic Cancer (PC) has a poor prognosis, with a 5-year survival rate of only 9%. Even after radical surgical procedures, PC patients have poor survival rates, with a high chance of relapse (70-80%). Imaging is involved in all aspects of the clinical management of PC, including detection and characterization of primary tumors and their resectability, assessment of vascular, perineural and lymphatic invasion and detection of distant metastases. The role of Positron Emission Tomography/Computed Tomography (PET/CT) in detecting PC is still controversial, with the international guidelines not recommending its routine use. However, in resectable PC, PET/CT may play a role in assessing PC stage and grade and potential resectability after neoadjuvant treatment. Quantitative image analysis (radiomics) and new PET/CT radiotracers account for future developments in metabolic imaging and may further improve the relevance of this technique in several aspects of PC. In the present review, the current state of the art and future directions of PET/CT in resectable PC are presented.

Pancreatic adenocarcinoma: A review of recent paradigms and advances in epidemiology, clinical diagnosis and management

Pancreatic cancer is one of the dreaded malignancies for both the patient and the clinician. The five-year survival rate of pancreatic adenocarcinoma (PDA) is as low as 2% despite multimodality treatment even in the best hands. As per the Global Cancer Observatory of the International Agency for Research in Cancer estimates of pancreatic cancer, by 2040, a 61.7% increase is expected in the total number of cases globally. With the widespread availability of next-generation sequencing, the entire genome of the tumors is being sequenced regularly, providing insight into their pathogenesis. As invasive PDA arises from pancreatic intraepithelial neoplasia and mucinous neoplasm and intraductal papillary neoplasm, screening for them can be beneficial as the disease is curable with resection at an early stage. Routine preoperative biliary drainage has no role in patients suffering from PDA with obstructive jaundice. If performed, metallic stents are preferred over plastic ones. Minimally invasive procedures are preferred to open procedures as they have less morbidity. The duct-to-mucosa technique for pancreaticojejunostomy is presently widely practiced. The role of intraperitoneal drains after surgery for PDA is controversial. Neoadjuvant chemoradiotherapy has been proven to have a significant role both in locally advanced as well as in resectable PDA. Many new regimens and drugs have been added in the arsenal of chemoradiotherapy for metastatic disease. The roles of immunotherapy and gene therapy in PDA are being investigated. This review article is intended to improve the understanding of the readers with respect to the latest updates of PDA, which may help to trigger new research ideas and make better management decisions.

Clinical Impact of 18F-FDG PET/CT in the Diagnostic Workup of Pancreatic Ductal Adenocarcinoma: A Systematic Review

In this review, the performance of fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in the diagnostic workup of pancreatic ductal adenocarcinoma (PDAC) is evaluated. A comprehensive literature search up to September 2020 was performed, selecting studies with the presence of: sample size ≥10 patients and index test (i.e., “FDG” or “18F-FDG” AND “pancreatic adenocarcinoma” or “pancreas cancer” AND “PET” or “positron emission tomography”). The methodological quality was evaluated using the revised quality assessment of diagnostic accuracy studies (QUADAS-2) tool and presented according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Basic data (authors, year of publication, country and study design), patients’ characteristics (number of enrolled subjects and age), disease phase, type of treatment and grading were retrieved. Forty-six articles met the adopted research criteria. The articles were divided according to the considered clinical context. Namely, besides conventional anatomical imaging, such as computed tomography (CT) and magnetic resonance imaging (MRI), molecular imaging with FDG PET/CT is an important tool in PDAC, for all disease stages. Further prospective studies will be necessary to confirm the cost-effectiveness of such imaging techniques by testing its real potential improvement in the clinical management of PDAC.

Impact of F-18 Fluorodeoxyglucose PET/CT and PET/MRI on Initial Staging and Changes in Management of Pancreatic Ductal Adenocarcinoma: A Systemic Review and Meta-Analysis

A systemic review and meta-analysis were conducted to investigate the diagnostic ability for staging and impact on management of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and PET/magnetic resonance imaging (MRI) in patients with pancreatic ductal adenocarcinoma. A comprehensive search was performed in four databases to retrieve studies of pancreatic ductal adenocarcinoma patients that have reported the diagnostic ability of FDG PET/CT and PET/MRI for detecting metastasis and the proportion of patients whose management was changed by its results. The sensitivity and specificity for detecting metastasis and the proportion of patients with management changes were pooled using a random-effects model. A total of 10 studies were included. The pooled sensitivity and specificity for detecting lymph node metastasis were 0.55 and 0.94, respectively, while the pooled sensitivity and specificity for detecting distant metastasis were 0.80 and 1.00, respectively. The areas under the summarized receiver operating characteristic curves for detecting lymph node and distant metastasis were 0.88 and 0.92, respectively. The pooled proportion of patients with management changes was 19%. FDG PET/CT and PET/MRI showed high diagnostic accuracy for detecting lymph node and distant metastasis in pancreatic ductal adenocarcinoma patients, and the use of these imaging tools led to management changes in a significant portion of these patients.

Prognostic value of 18FDG PET/CT volumetric parameters in the survival prediction of patients with pancreatic cancer

PURPOSE

To investigate the value of 18 FDG PET/CT volumetric parameters in the prediction of overall survival (OS) in patients with pancreatic cancer and also, assess their independence relative to well-established clinico-pathological variables.

METHODS

We conducted a retrospective analysis of patients with a confirmed diagnosis of pancreatic cancer who underwent 18 FDG PET/CT. The tumour maximum standardised uptake value (SUVmax) in addition to SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated. The prognostic value of 18 FDG PET/CT and clinico-pathological parameters for OS were assessed using univariate and multivariable analyses.

RESULTS

A sum of 89 patients were analysed in this study. Median survival for patients categorised as having high TLG (≥55) and low TLG (<55) was 18 vs 5 months (p < 0.001). Similarly, the respective high vs low SUVmean, MTV and SUVmax were 18 vs 6 months (p = 0.001), 16 vs 6 months (p = 0.002) and 18 vs 6 months (p = 0.001). Univariate analysis showed SUVmax, SUVmean, MTV, TLG, tumour size, tumour differentiation and presence of distant metastasis as prognostic factors for OS. On multivariable analysis, TLG (HR 2.0, 95% CI 1.26-3.18, p = 0.004) and the presence of distant metastasis (HR 3.37, 95% CI 1.97-5.77, p < 0.001) emerged as independent prognostic factors. Subgroup analysis identified TLG as the only significant PET metric after adjusting for the presence of distant metastasis.

CONCLUSIONS

18 FDG PET/CT is a useful tool in the preoperative evaluation of patients with pancreatic cancer. Tumour TLG offer an independent prognostic value in both potentially operable and metastatic disease settings.

The Role of Positron Emission Tomography in Pancreatic Cancer and Gallbladder Cancer

¹⁸F-FDG-PET is complementary to conventional imaging in patients with clinical suspicion for exocrine pancreatic malignancies. It has similar if not superior sensitivity and specificity for detection of cancer, and when combined with contrast enhanced anatomic imaging of the abdomen, can improve diagnostic accuracy and aid in staging, assessment for resectability, radiation therapy planning, and prognostication. Various metabolic pathways affect FDG uptake in pancreatic ductal adenocarcinoma. The degree of uptake reflects histopathology, aggressiveness, metastatic potential, and metabolic profile of malignant cell and their interaction with cancer stroma. After treatment, FDG-PET is useful for detection of residual or recurrent cancer and can be used to assess and monitor response to therapy in unresectable or metastatic disease. The degree and pattern of uptake combined with other imaging features are useful in characterization of incidental pancreatic lesions and benign processes such as inflammation. Several novel PET radiopharmaceuticals have been developed to improve detection and management of pancreatic cancer. Gallbladder carcinoma is typically FDG avid and when anatomic imaging is equivocal PET can be used to assess metastatic involvement with high specificity and inform subsequent management.

Pancreatic adenocarcinoma with early esophageal metastasis: A case report and review of literature

BACKGROUND

Pancreatic adenocarcinoma is an aggressive malignancy with a high propensity to metastasize. Esophageal metastasis manifesting as dysphagia is rarely reported in the literature and has not to our knowledge been reported prior to the appearance of the primary disease.

CASE SUMMARY

A patient presented with progressive dysphagia to solids and a persistent earache. Computed tomography of the neck and chest revealed a 3.0 cm × 1.8 cm heterogeneous mass originating from the upper third of the esophagus, necrotic cervical and supraclavicular lymphadenopathy, and bilateral pulmonary nodules. She underwent a core needle biopsy of a right cervical node, which suggested a well-differentiated adenocarcinoma of unknown primary. She had an upper endoscopy with biopsy of the esophageal mass suggestive of a well-differentiated adenocarcinoma. Positron emission tomography imaging revealed increased uptake in the esophageal mass, cervical, and mediastinal lymph nodes. She was started on folinic acid, fluorouracil, and oxaliplatin. Prior to initiation of cycle 8, the patient was found to have a pancreatic body mass that was not present on prior radiographic imaging, confirmed by endoscopic ultrasonography and biopsy to be pancreatic adenocarcinoma. CA19-9 was > 10000 U/mL, suggesting a primary pancreaticobiliary origin.

CONCLUSION

Esophageal metastasis diagnosed before primary pancreatic adenocarcinoma is rare. This case highlights the profound metastatic potential of pancreatic adenocarcinoma.

The Role of PET/CT in the Imaging of Pancreatic Neoplasms

Pancreas cancer is a complex disease and its prognosis is related to the origin of the tumor cell as well as the stage of disease at the time of diagnosis. Pancreatic adenocarcinomas derive from the exocrine pancreas and are the fourth leading cause of cancer-related deaths in the United States, while well-differentiated pancreatic neuroendocrine tumors (pNETs) derived from the endocrine part of the pancreas are rare and characterized by a slow growth and good life expectancy. Surgery is the only curative treatment approach, and an accurate assessment of resectability is of paramount importance in order to avoid futile procedures. The role of molecular imaging with positron emission tomography and computed tomography ranges from indispensable for pNETs to controversial for certain scenarios in pancreatic adenocarcinomas. This review article aims to overview molecular pancreatic imaging.

18F-FDG PET/CT in pancreatic adenocarcinoma: A role at initial imaging staging?

Pancreatic ductal adenocarcinoma represents 90% of all pancreatic tumors. The only hope for prolonged survival in patients with this condition still remains surgery with complete R0 resection. Initial imaging has a pivotal role to identify patients who are eligible to curative surgery and those who may benefit of neoadjuvant chemotherapy. This review provides an analysis of the recent literature on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in pancreatic adenocarcinoma. Performances of FDG PET in the detection of lymph node involvement and metastatic spread at initial staging and those in the assessment of response to treatment are described.

Natural History of Pancreatic Ductal Adenocarcinoma Diagnosed During Observation of Other Organ Cancers

BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is a rapidly progressive malignancy that exhibits an extremely poor prognosis, with most cases diagnosed at an advanced stage. To date, few reports have explored the natural history of PDAC, and the period leading up to the detection of PDAC as a tumor with contrast-enhanced computed tomography (CECT) remains unclear. Here, we report 3 PDAC cases diagnosed incidentally by repeating imaging examinations during observation of other organ cancers. CASE REPORT Two patients were undergoing postoperative follow-up for colorectal cancer; owing to the elevation of serum CA19-9 or dilatation of the main pancreatic duct, both cases were finally diagnosed with PDAC. Another patient was administered neoadjuvant chemotherapy for a gastrointestinal stromal tumor; the fluorodeoxyglucose uptake in the pancreas with fluorodeoxyglucose positron emission tomography for the treatment assessment led to the diagnosis of PDAC. All patients underwent frequent CECT for assessment of other diseases, and PDAC became visible with CECT within 3-4 months of the appearance of indirect findings of PDAC. CONCLUSIONS The period leading up to the detection of PDAC as a tumor with CECT was approximately 3-4 months. These cases suggest that additional imaging examinations should be performed when the indirect findings of PDAC are noted. This report adds value to the literature by elucidating the natural course of PDAC.

Role of contrast-enhanced 18F-FDG PET/CT imaging in the diagnosis and staging of renal tumors

PURPOSE

The objectives of this prospective study are to compare intravenous contrast-enhanced (CE) fluorine-18-fluorodeoxyglucose (F-FDG) PET/computed tomography (CE F-FDG PET/CT) with conventional methods (CT/MRI) and to evaluate the relationship of maximum standardized uptake value (SUVmax) with Fuhrman grade in patients with renal tumors.

PATIENTS AND METHODS

A total of 62 patients [35 males and 27 females; mean age 55.8±12.7 (range: 27-81) years] were enrolled in the study. CE F-FDG PET/CT scanning included whole-body (early) and abdominal imaging (late) 1 and 2 h after intravenous F-FDG administration, respectively. SUVmax was calculated for primary tumors. CE F-FDG PET/CT and CT/MRI findings were compared with respect to primary tumors and staging.

RESULTS

The sensitivity of CE F-FDG PET/CT in primary tumor detection was 98%, which was very close to that of CT/MRI (100%). CE F-FDG PET/CT resulted in correct staging in 84% of the cases, compared with 68% of the cases with conventional methods (52 vs. 42 patients). SUVmax values of early PET for the primary tumors were significantly correlated with the Fuhrman grades (P<0.001). CE F-FDG PET/CT enabled the detection of synchronous tumors in four patients, one of which was incorrectly diagnosed as having metastasis by CT. Distant metastases were detected in 16 patients with CE F-FDG PET/CT and in 13 patients with routine conventional methods.

CONCLUSION

CE F-FDG PET/CT showed similar results compared with CT/MRI in the detection of primary tumors, but it was superior to conventional methods in the detection of metastasis and staging. Given the highly significant correlation between SUVmax values and the Fuhrman grading, CE F-FDG PET/CT may play a significant role in the evaluation of patient prognosis.

PET-PANC: multicentre prospective diagnostic accuracy and health economic analysis study of the impact of combined modality 18fluorine-2-fluoro-2-deoxy-d-glucose positron emission tomography with computed tomography scanning in the diagnosis and management of pancreatic cancer

BACKGROUND

Pancreatic cancer diagnosis and staging can be difficult in 10-20% of patients. Positron emission tomography (PET)/computed tomography (CT) adds precise anatomical localisation to functional data. The use of PET/CT may add further value to the diagnosis and staging of pancreatic cancer.

OBJECTIVE

To determine the incremental diagnostic accuracy and impact of PET/CT in addition to standard diagnostic work-up in patients with suspected pancreatic cancer.

DESIGN

A multicentre prospective diagnostic accuracy and clinical value study of PET/CT in suspected pancreatic malignancy.

PARTICIPANTS

Patients with suspected pancreatic malignancy.

INTERVENTIONS

All patients to undergo PET/CT following standard diagnostic work-up.

MAIN OUTCOME MEASURES

The primary outcome was the incremental diagnostic value of PET/CT in addition to standard diagnostic work-up with multidetector computed tomography (MDCT). Secondary outcomes were (1) changes in patients' diagnosis, staging and management as a result of PET/CT; (2) changes in the costs and effectiveness of patient management as a result of PET/CT; (3) the incremental diagnostic value of PET/CT in chronic pancreatitis; (4) the identification of groups of patients who would benefit most from PET/CT; and (5) the incremental diagnostic value of PET/CT in other pancreatic tumours.

RESULTS

Between 2011 and 2013, 589 patients with suspected pancreatic cancer underwent MDCT and PET/CT, with 550 patients having complete data and in-range PET/CT. Sensitivity and specificity for the diagnosis of pancreatic cancer were 88.5% and 70.6%, respectively, for MDCT and 92.7% and 75.8%, respectively, for PET/CT. The maximum standardised uptake value (SUVmax.) for a pancreatic cancer diagnosis was 7.5. PET/CT demonstrated a significant improvement in relative sensitivity (p = 0.01) and specificity (p = 0.023) compared with MDCT. Incremental likelihood ratios demonstrated that PET/CT significantly improved diagnostic accuracy in all scenarios (p < 0.0002). PET/CT correctly changed the staging of pancreatic cancer in 56 patients (p = 0.001). PET/CT influenced management in 250 (45%) patients. PET/CT stopped resection in 58 (20%) patients who were due to have surgery. The benefit of PET/CT was limited in patients with chronic pancreatitis or other pancreatic tumours. PET/CT was associated with a gain in quality-adjusted life-years of 0.0157 (95% confidence interval -0.0101 to 0.0430). In the base-case model PET/CT was seen to dominate MDCT alone and is thus highly likely to be cost-effective for the UK NHS. PET/CT was seen to be most cost-effective for the subgroup of patients with suspected pancreatic cancer who were thought to be resectable.

CONCLUSION

PET/CT provided a significant incremental diagnostic benefit in the diagnosis of pancreatic cancer and significantly influenced the staging and management of patients. PET/CT had limited utility in chronic pancreatitis and other pancreatic tumours. PET/CT is likely to be cost-effective at current reimbursement rates for PET/CT to the UK NHS. This was not a randomised controlled trial and therefore we do not have any information from patients who would have undergone MDCT only for comparison. In addition, there were issues in estimating costs for PET/CT. Future work should evaluate the role of PET/CT in intraductal papillary mucinous neoplasm and prognosis and response to therapy in patients with pancreatic cancer.

STUDY REGISTRATION

Current Controlled Trials ISRCTN73852054 and UKCRN 8166.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The Role of 18F-FDG PET/CT and PET/MRI in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a difficult disease to treat and continues to portend a poor prognosis, as most patients are unresectable at diagnosis. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) combined with CT (PET/CT) has been a cornerstone in oncological imaging of different cancers; however, the role of PET/CT in PDAC is continually evolving and currently not well established. Studies have shown the potential of PET/CT in guiding the management of patients with PDAC, with possible added benefit over anatomic imaging with CT or MRI in certain scenarios. PET/CT may be useful in diagnosis, initial staging, treatment response assessment, differentiation of recurrent tumor from post-treatment fibrosis, and radiotherapy planning. Additionally, PET/CT may be a cost-effective modality due to upstaging of patients originally deemed as surgical candidates. Recently, the advent of simultaneous PET/MRI represents an exciting advancement in hybrid functional imaging with potential applications in the imaging of PDAC. The advantages of PET/MRI include simultaneous acquisition to improve registration of fusion images, lower radiation dose, superior soft tissue contrast, and availability of multiparametric imaging. Studies are underway to evaluate the utility of PET/MRI in PDAC, including in initial staging and treatment response assessment and to determine the subgroup of patients that will benefit from PET/MRI. Further studies are warranted in both PET/CR and PET/MRI to better understand the role of these modalities in PDAC.

Targeted Molecular Imaging of Pancreatic Cancer with a Miniature Endoscope

It is highly desirable to develop novel approaches to improve patient survival rate of pancreatic cancer through early detection. Here, we present such an approach based on photoacoustic and fluorescence molecular imaging of pancreatic tumor using a miniature multimodal endoscope in combination with targeted multifunctional iron oxide nanoparticles (IONPs). A novel fan-shaped scanning mechanism was developed to minimize the invasiveness for endoscopic imaging of pancreatic tumors. The results show that the enhancements in photoacoustic and fluorescence signals using amino-terminal fragment (ATF) targeted IONPs were ~four to six times higher compared to that using non-targeted IONPs. Our study indicates the potential of the combination of the multimodal photoacoustic-fluorescence endoscopy and targeted multifunctional nanoparticles as an efficient tool to provide improved specificity and sensitivity for pancreatic cancer detection.

Fluorodeoxyglucose-positron emission tomography/computed tomography performs better than contrast-enhanced computed tomography for metastasis evaluation in the initial staging of pancreatic adenocarcinoma

OBJECTIVE

To evaluate the additional role of FDG-PET/CT to the conventional multiphasic CECT in the initial staging of pancreatic adenocarcinoma.

METHODS

54 patients diagnosed with pathologically proven pancreatic malignancy underwent FDG-PET/CECT. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal and metastatic staging were calculated. The statistical difference was calculated by McNemar's test.

RESULTS

Of 54 patients, 15 had distal metastasis. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal staging were 33 vs 89%, 84 vs 100%, 67 vs 100%, 60 vs 90%, and 59 vs 95%, respectively, p < 0.001. The sensitivity, specificity, PPV, NPV, and accuracy of CECT for metastatic staging were 73, 87, 69, 89, and 83%, whereas the accuracy of PET/CT was 100%, p = 0.01. By correctly characterizing unsuspected distant lesions, PET/CT could change management in 19% of patients.

CONCLUSION

FDG-PET/CT can contribute to change in the management in almost one of every five patients of PA evaluated with the standard investigations during the initial staging.

Utility of 18 fludeoxyglucose in preoperative positon-emission tomography-computed tomography (PET-CT) in the early diagnosis of exocrine pancreatic cancer: A study of 139 resected cases

INTRODUCTION

In pancreatic ductal adenocarcinoma (PDA), surgical resection is the only curative treatment, but due to its late clinical presentation only 15-25% patients are candidates for curative resection. The aim of this prospective, single-center study is to determine the diagnostic utility of preoperative PET-CT for early detection of PDA and early panIN lesions.

METHODS

We studied the histopathological features of PDA and different panIN lesions in 139 surgical samples from patients undergoing pancreatic resection (from 2010-2014), comparing these results with preoperative PET-CT and MDCT study. For tumor diagnosis in PET-CT maximum standard SUV 2.5 was used. Pancreatic baseline SUVmax is the maximum uptake of the radiotracer 18-2FDG on the ROI curve determined for the area of the normal pancreas after pathological reassessment with areas not affected by tumours or preneoplastic lesions. Tumour Uptake Index is the ratio between the tumour SUVmax and pancreatic baseline SUVmax.

RESULTS

Using an standard maximum SUV value of 2.5, PET-CT sensitivity was 77.7% (108 of the 139 cases) against 75.5% (105 of the 139 cases) of MDCT. But when we combined this value with maximum SUV of normal pancreatic tissue from each patient, PET-CT sensitivity improved its value to 94.9%.

CONCLUSION

A combination of studies of PET-CT in tumor and non-tumor tissue of each patient might be a very useful diagnostic tool not only for preoperative diagnosis of PDA, but also for early panIN lesions.

Diagnostic accuracy of different imaging modalities following computed tomography (CT) scanning for assessing the resectability with curative intent in pancreatic and periampullary cancer

BACKGROUND

Periampullary cancer includes cancer of the head and neck of the pancreas, cancer of the distal end of the bile duct, cancer of the ampulla of Vater, and cancer of the second part of the duodenum. Surgical resection is the only established potentially curative treatment for pancreatic and periampullary cancer. A considerable proportion of patients undergo unnecessary laparotomy because of underestimation of the extent of the cancer on computed tomography (CT) scanning. Other imaging methods such as magnetic resonance imaging (MRI), positron emission tomography (PET), PET-CT, and endoscopic ultrasound (EUS) have been used to detect local invasion or distant metastases not visualised on CT scanning which could prevent unnecessary laparotomy. No systematic review or meta-analysis has examined the role of different imaging modalities in assessing the resectability with curative intent in patients with pancreatic and periampullary cancer.

OBJECTIVES

To determine the diagnostic accuracy of MRI, PET scan, and EUS performed as an add-on test or PET-CT as a replacement test to CT scanning in detecting curative resectability in pancreatic and periampullary cancer.

SEARCH METHODS

We searched MEDLINE, Embase, Science Citation Index Expanded, and Health Technology Assessment (HTA) databases up to 5 November 2015. Two review authors independently screened the references and selected the studies for inclusion. We also searched for articles related to the included studies by performing the "related search" function in MEDLINE (OvidSP) and Embase (OvidSP) and a "citing reference" search (by searching the articles that cite the included articles).

SELECTION CRITERIA

We included diagnostic accuracy studies of MRI, PET scan, PET-CT, and EUS in patients with potentially resectable pancreatic and periampullary cancer on CT scan. We accepted any criteria of resectability used in the studies. We included studies irrespective of language, publication status, or study design (prospective or retrospective). We excluded case-control studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed data extraction and quality assessment using the QUADAS-2 (quality assessment of diagnostic accuracy studies - 2) tool. Although we planned to use bivariate methods for analysis of sensitivities and specificities, we were able to fit only the univariate fixed-effect models for both sensitivity and specificity because of the paucity of data. We calculated the probability of unresectability in patients who had a positive index test (post-test probability of unresectability in people with a positive test result) and in those with negative index test (post-test probability of unresectability in people with a positive test result) using the mean probability of unresectability (pre-test probability) from the included studies and the positive and negative likelihood ratios derived from the model. The difference between the pre-test and post-test probabilities gave the overall added value of the index test compared to the standard practice of CT scan staging alone.

MAIN RESULTS

Only two studies (34 participants) met the inclusion criteria of this systematic review. Both studies evaluated the diagnostic test accuracy of EUS in assessing the resectability with curative intent in pancreatic cancers. There was low concerns about applicability for most domains in both studies. The overall risk of bias was low in one study and unclear or high in the second study. The mean probability of unresectable disease after CT scan across studies was 60.5% (that is 61 out of 100 patients who had resectable cancer after CT scan had unresectable disease on laparotomy). The summary estimate of sensitivity of EUS for unresectability was 0.87 (95% confidence interval (CI) 0.54 to 0.97) and the summary estimate of specificity for unresectability was 0.80 (95% CI 0.40 to 0.96). The positive likelihood ratio and negative likelihood ratio were 4.3 (95% CI 1.0 to 18.6) and 0.2 (95% CI 0.0 to 0.8) respectively. At the mean pre-test probability of 60.5%, the post-test probability of unresectable disease for people with a positive EUS (EUS indicating unresectability) was 86.9% (95% CI 60.9% to 96.6%) and the post-test probability of unresectable disease for people with a negative EUS (EUS indicating resectability) was 20.0% (5.1% to 53.7%). This means that 13% of people (95% CI 3% to 39%) with positive EUS have potentially resectable cancer and 20% (5% to 53%) of people with negative EUS have unresectable cancer.

AUTHORS' CONCLUSIONS

Based on two small studies, there is significant uncertainty in the utility of EUS in people with pancreatic cancer found to have resectable disease on CT scan. No studies have assessed the utility of EUS in people with periampullary cancer.There is no evidence to suggest that it should be performed routinely in people with pancreatic cancer or periampullary cancer found to have resectable disease on CT scan.

The endoscopist's role in the diagnosis and management of pancreatic cancer

Pancreatic cancer remains one of the most lethal malignancies with little improvement in survival over the past several decades in spite of advances in imaging, risk factor identification, surgical technique and chemotherapy. This disappointing outcome is mainly due to failures to make an early diagnosis. In fact, the majority of the patients present with inoperable advanced stages of the disease. Though some of the new tumor markers are promising, we are still in search of the one that has a high sensitivity and accuracy, yet is inexpensive and easy to obtain. The paradigm of management has shifted from up-front surgery followed by adjuvant chemotherapy to neoadjuvant chemoradiation followed by surgery, especially for borderline resectable cancers and even for some resectable cancers. In this article, we will critically assess the limitations of tumor markers and review the advancements in endoscopic techniques in the management of pancreatic cancer.

Personalized Clinical Decision Making in Gastrointestinal Malignancies: The Role of PET

Gastrointestinal malignancies comprise a heterogeneous group of diseases that include both common and rare diseases with very different presentations and prognoses. The mainstay of treatment is surgery in combination with preoperative and adjuvant chemotherapy depending on clinical presentation and initial stages. This article outlines the potential use of fluorodeoxyglucose-PET/CT in clinical decision making with special regard to preoperative evaluation and response assessment in gastric cancer (including the gastroesophageal junction), pancreatic cancer (excluding neuroendocrine tumors), colorectal cancer, and gastrointestinal stromal tumors.

18F-FLT PET imaging of cellular proliferation in pancreatic cancer

Pancreatic ductal adenocarcinoma is known for its poor prognosis. Since the development of computerized tomography, magnetic resonance and endoscopic ultrasound, novel imaging techniques have struggled to get established in the management of patients diagnosed with pancreatic adenocarcinoma for several reasons. Thus, imaging assessment of pancreatic cancer remains a field with scope for further improvement. In contrast to cross-sectional anatomical imaging methods, molecular imaging modalities such as positron emission tomography (PET) can provide information on tumour function. Particularly, tumour proliferation may be assessed by measurement of intracellular thymidine kinase 1 (TK1) activity level using thymidine analogues radiolabelled with a positron emitter for use with PET. This approach, has been widely explored with [(18)F]-fluoro-3'-deoxy-3'-L-fluorothymidine ((18)F-FLT) PET. This manuscript reviews the rationale and physiology behind (18)F-FLT PET imaging, with special focus on pancreatic cancer and other gastrointestinal malignancies. Potential benefit and challenges of this imaging technique for diagnosis, staging and assessment of treatment response in abdominal malignancies are discussed.

Contrast Media in PET/Computed Tomography Imaging

Is there a need for the contrast-enhanced PET/computed tomography (CT) scan or is the low-dose, non-contrast-enhanced PET/CT scan sufficient? The topic has been debated time and again. Although low-dose noncontrast CT serves the purpose of simple anatomic correlation and attenuation correction of PET images, many times patients have to undergo additional contrast-enhanced diagnostic imaging modalities, which may lead to a delay in decision-making. In this review, the authors have addressed various such issues related to the use of contrast agents and special techniques of clinical interest based on their utility in dual-modality PET/CT.

Hybrid imaging for pancreatic malignancy: clinical applications, merits, limitations, and pitfalls

The role of PET/CT in pancreatic malignancy is evolving with new scientific evidence emerging continuously. PET/CT applications in imaging the pancreas and its organ-specific merits, limitations, and potential pitfalls are still evolving. This article provides an overview of the state-of-the-art applications of PET/CT imaging in evaluating pancreatic malignancy, comparing with conventional imaging modalities, such as contrast-enhanced CT and MRI. Current PET/MRI is also reviewed, along with brief discussion on cost-benefit analysis.

Role of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography in gastrointestinal cancers

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a routine imaging modality for many malignancies and its use is currently increasing. In the present review article, we will summarize the evidence for FDG-PET/CT use in digestive cancers (excluding neuroendocrine tumours), and review the existing recommendations. While PET/CT is nowadays considered to be an important tool in the initial workup of oesophageal and anal cancers, new data are emerging regarding its use in assessing therapeutic efficacy, radiotherapy treatment planning, and detection of recurrence in case of isolated tumour marker elevation. Moreover, PET/CT may help decision making by detecting distant metastatic sites especially in potentially resectable metastatic colorectal cancer and, to a lesser extent, in localized gastric and pancreatic cancers. Finally, incidental focal colonic FDG uptakes require exploration by colonoscopy, as they are often associated with premalignant or malignant lesions.

Consequences of additional use of contrast-enhanced (18)F-FDG PET/CT in target volume delineation and dose distribution for pancreatic cancer

OBJECTIVE

To compare the differences between contrast-enhanced (CE) fluorine-18 fludeoxyglucose ((18)F-FDG) positron emission tomography (PET)/CT and CECT in target volume delineation and radiotherapy (RT) dose distribution, and to evaluate the sparing of organs at risk (OARs) in the treatment plan of locally advanced pancreatic cancer (LAPC).

METHODS

21 consecutive patients with LAPC with histologically or cytologically confirmed adenocarcinoma underwent both non-CECT and (18)F-FDG scans; 11 of whom also underwent CECT scans. Intensity-modulated RT plans (prescribed dose, 54 Gy) were constructed to cover the corresponding gross tumour volume (GTV). The differences among GTVCT, GTVPET, GTVPET-CT and OARs in these different image sets as well as the uniformity of target dose were analysed.

RESULTS

The mean non-CE GTVCT, GTVPET and GTVPET-CT were 76.9 ± 47.8, 47.0 ± 40.2 and 44.5 ± 34.7 cm(3) (mean ± standard deviation), respectively. The non-CE GTVPET-CT was significantly smaller than the non-CE GTVCT (p < 0.001). The CE GTVPET-CT was significantly smaller than the CE GTVCT (p = 0.033). For both the non-CE GTVCT and the CE GTVCT, the intestine V40 (the percentage of the intestine volume irradiated by 40 Gy), intestine V50, intestine Dmax (the mean maximum dose), cord Dmax, left kidney V30, right kidney V30, left kidney Dmean (the mean dose), right kidney Dmean and liver V30 were 5.90%, 2.52%, 5500 cGy, 2194 cGy, 3.40%, 0.68%, 747 cGy, 550 cGy and 5.37%, respectively. There are significant differences between the non-CE CT and the non-CE PET-CT in intestine Dmax (p = 0.023) and right kidney Dmean (p = 0.029).

CONCLUSION

Co-registration of (18)F-FDG PET with CECT may improve the accuracy of GTV delineation in LAPC and might reduce the adverse effect of irradiation.

ADVANCES IN KNOWLEDGE

Individual adaptation of RT based on functional CE (18)F-FDG PET/CT imaging is possible and highly promising in LAPC.

Cross-modality PET/CT and contrast-enhanced CT imaging for pancreatic cancer

AIM: To explore the diagnostic value of the cross-modality fusion images provided by positron emission tomography/computed tomography (PET/CT) and contrast-enhanced CT (CECT) for pancreatic cancer (PC).

METHODS: Data from 70 patients with pancreatic lesions who underwent CECT and PET/CT examinations at our hospital from August 2010 to October 2012 were analyzed. PET/CECT for the cross-modality image fusion was obtained using TureD software. The diagnostic efficiencies of PET/CT, CECT and PET/CECT were calculated and compared with each other using a χ² test. P < 0.05 was considered to indicate statistical significance.

RESULTS: Of the total 70 patients, 50 had PC and 20 had benign lesions. The differences in the sensitivity, negative predictive value (NPV), and accuracy between CECT and PET/CECT in detecting PC were statistically significant (P < 0.05 for each). In 15 of the 31 patients with PC who underwent a surgical operation, peripancreatic vessel invasion was verified. The differences in the sensitivity, positive predictive value, NPV, and accuracy of CECT vs PET/CT and PET/CECT vs PET/CT in diagnosing peripancreatic vessel invasion were statistically significant (P < 0.05 for each). In 19 of the 31 patients with PC who underwent a surgical operation, regional lymph node metastasis was verified by postsurgical histology. There was no statistically significant difference among the three methods in detecting regional lymph node metastasis (P > 0.05 for each). In 17 of the 50 patients with PC confirmed by histology or clinical follow-up, distant metastasis was confirmed. The differences in the sensitivity and NPV between CECT and PET/CECT in detecting distant metastasis were statistically significant (P < 0.05 for each).

CONCLUSION: Cross-modality image fusion of PET/CT and CECT is a convenient and effective method that can be used to diagnose and stage PC, compensating for the defects of PET/CT and CECT when they are conducted individually.

Utility of PET/CT in diagnosis, staging, assessment of resectability and metabolic response of pancreatic cancer

Pancreatic cancer is one of the most common gastrointestinal tumors, with its incidence staying at a high level in both the United States and China. However, the overall 5-year survival rate of pancreatic cancer is still extremely low. Surgery remains the only potential chance for long-term survival. Early diagnosis and precise staging are crucial to make proper clinical decision for surgery candidates. Despite advances in diagnostic technology such as computed tomography (CT) and endoscopic ultrasound, diagnosis, staging and monitoring of the metabolic response remain a challenge for this devastating disease. Positron emission tomography/CT (PET/CT), a relatively novel modality, combines metabolic detection with anatomic information. It has been widely used in oncology and achieves good results in breast cancer, lung cancer and lymphoma. Its utilization in pancreatic cancer has also been widely accepted. However, the value of PET/CT in pancreatic disease is still controversial. Will PET/CT change the treatment strategy for potential surgery candidates? What kind of patients benefits most from this exam? In this review, we focus on the utility of PET/CT in diagnosis, staging, and assessment of resectability of pancreatic cancer. In addition, its ability to monitor metabolic response and recurrence after treatment will be emphasis of discussion. We hope to provide answers to the questions above, which clinicians care most about.

[18F]Fluorodeoxyglucose PET/Computed Tomography in Gastrointestinal Malignancies

This article discusses the current state-of-the-art application of 2-deoxy-2-[(18)F]fluoro-d-glucose (FDG)-PET and FDG-PET/computed tomography (CT) in the management of patients with gastrointestinal malignancies. Gastrointestinal malignancies include many different cell types, several common malignancies of which may be imaged by FDG-PET/CT. This review focuses on gastric carcinoma, pancreatic carcinoma, hepatocellular carcinoma, cholangiocarcinoma, colorectal carcinoma, and stroma cell tumors. The role of FDG-PET/CT in staging these malignancies is discussed, in addition to (re)staging, detection of recurrent disease, patient selection/prognostication, and response assessment, using the currently available literature.

Staging accuracy of pancreatic cancer: comparison between non-contrast-enhanced and contrast-enhanced PET/CT

PURPOSE

Our aim was to clarify the diagnostic impact of contrast-enhanced (CE) (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) for staging of pancreatic cancer compared to non-CE PET/CT.

METHOD AND MATERIALS

Between April 2006 and November 2009, a total of 95 patients (age range, 36-83 years [mean age, 67]) with primary pancreatic cancer underwent (18)F-FDG PET/CT examinations. Diagnostic accuracy was compared between non-CE PET/CT and CE PET/CT. Images were analyzed visually and quantitatively by two blinded reviewers. Reference standard was histological examination in 48 patients (51%) and/or confirmation of an obvious progression in number and/or size of the lesions on follow-up CT examinations in 47 patients (49%).

RESULTS

For T-staging, invasion of duodenum (n=20, 21%), mesentery (n=12, 13%), and retroperitoneum (n=13, 14%) was correctly diagnosed by both modalities. The ROC analyses revealed that the Az values of celiac artery (CA), common hepatic artery (CHA), splenic artery (SV), and superior mesenteric vein (SMV) invasion were significantly higher in the CE PET/CT group for both readers. Nodal metastasis was correctly diagnosed by CE PET/CT in 38 patients (88%) and by non-CE PET/CT in 45 patients (87%). Diagnostic accuracies of nodal metastasis in two modalities were similar. Using CE PET/CT, distant metastasis, scalene node metastasis, and peritoneal dissemination were correctly assigned in 39 patients (91%), while interpretation based on non-CE PET/CT revealed distant metastasis, scalene node metastasis, and peritoneal dissemination in 42 patients (81%). Diagnostic accuracy of distant metastasis, scalene node metastasis, and peritoneal dissemination with CE PET/CT was significantly higher than that of non-CE PET/CT (p<0.05).

CONCLUSION

CE PET/CT allows a more precise assessment of distant metastasis, scalene node metastasis, and peritoneal dissemination in patients with pancreatic cancer.

Impact of concurrent diagnostic level CT with PET/CT on the utilization of stand-alone CT and MRI in the management of head and neck cancer patients

PURPOSE OF THE REPORT

This study aims to determine if the expansion of a PET/CT service to include simultaneous contrast-enhanced CT with PET (PET/DCT) leads to a reduction of supplemental diagnostic CT (sCT) performed within a 6-month period centered around PET/CT for initial treatment planning of patients with head and neck cancers.

PATIENTS AND METHODS

There were 91 patients with head and neck cancers who had a non-contrast-enhanced PET/CT with CT (PET/aCT), and 153 patients had a PET/DCT. We compared the utilization of sCT before and after PET/aCT or PET/DCT. Logistic regression analysis, unpaired t test, and analysis of variance were performed.

RESULTS

Among the 75 patients who had sCT scans in the 3 months before their PET/CT, 44 (58.7%) scans were performed in patients who had a PET/aCT and 31 (41.3%) scans were performed in patients who had a PET/DCT (P < 0.001). Among the 36 patients who had a CT in the 3 months after their baseline PET/CT, 23 (63.9%) were performed in patients who had a baseline PET/aCT and 13 (36.1%) were performed in patients who had a baseline PET/DCT (P < 0.001). The adjusted odds ratio for performing an sCT within 3 months before and after baseline PET/DCT scan as opposed to a PET/aCT scan was 0.24 (P < 0.001) and 0.31 (P < 0.01), respectively.

CONCLUSIONS

The opportunity to order simultaneous diagnostic CT imaging with PET/CT (PET/DCT) reduced the referrals for stand-alone CT neck imaging in the initial treatment plan of head and neck cancer patients when compared to a service that only offered the PET/CT scan with CT for attenuation correction (PET/aCT).

Contrast-enhanced [18 F] fluorodeoxyglucose-positron emission tomography/computed tomography in clinical oncology: tumor-, site-, and question-based comparison with standard positron emission tomography/computed tomography

BACKGROUND

The present study aimed to evaluate the added value of contrast-enhanced computed tomography (ceCT) in comparison to standard, non-enhanced CT in the context of a combined positron emission tomography (PET)/CT examination by means of a tumor-, site-, and clinical question-based approach.

METHODS

Analysis was performed in 202 patients undergoing PET/CT consisting of a multiphase CT protocol followed by a whole-body PET. The Cochran Q test was performed, followed by a multiple comparisons correction (McNemar test and Bonferroni adjustment), to compare standard and contrast-enhanced PET (cePET/CT). Histopathology or clinical-radiologic follow-up greater than 1 year was used as a reference.

RESULTS

cePET/CT showed significantly different results with respect to standard PET/CT in head and neck and gastrointestinal cancer (P = 0.02 and 0.0002, respectively), in the evaluation of lesions located in the abdomen (P = 0.009), and in the context of disease restaging (P = 0.003). In all these clinical scenarios, adding ceCT resulted in a distinct benefit, by yielding a higher percentage of change in patient management.

CONCLUSION

These data strongly underline the importance of strictly selecting patients for the combined exam. In particular, patient selection should not be driven solely by mere tumor classification, but should also account for the clinical question and the anatomical location of the neoplastic disease, which can significantly impact patient management.

Usefulness of F-18-fluorodeoxyglucose positron emission tomography to confirm suspected pancreatic cancer: a meta-analysis

INTRODUCTION

Pancreatic cancer is among the five most lethal malignancies in the world. Unfortunately, many malignant tumors go undetected by the current primary diagnostic tools. (18)FDG-PET and (18)FDG-PET/CT might be useful to confirm suspected pancreatic cancer.

METHODS

A meta-analysis was performed using all major search engines. Methodological quality of included studies was assessed as well as quality of the PET-protocol. The following pooled estimates served as primary outcome measures: sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy.

RESULTS

Thirty-five studies were included. Pooled estimates for (18)FDG-PET were: sensitivity 90%, specificity 76%, PPV 90%, NPV 76% and accuracy 86%. Pooled estimates for (18)FDG-PET/CT were: sensitivity 90%, specificity 76%, PPV 89%, NPV 78% and accuracy 86%. The pooled sensitivity and specificity for (18)FDG-PET to differentiate between pancreatic cancer and chronic pancreatitis were 90% and 84%, respectively.

CONCLUSION

Both (18)FDG-PET and (18)FDG-PET/CT offer no benefit over the current primary diagnostic tools in diagnosing pancreatic cancer. However, the (18)FDG-PET/CT systems are still improving. We should investigate the sensitivity and specificity of these new systems while reevaluating the tradeoff between false positive and false negative results. Yet, (18)FDG-PET/CT may have a role in the staging of pancreatic cancer, in survival prediction, and may add to other diagnostic information, like histology.