Gustavo Mercier

18F-FDG Metabolic Tumor Volume and Total Glycolytic Activity of Oral Cavity and Oropharyngeal Squamous Cell Cancer: Adding Value to Clinical Staging

18F-FDG metabolic tumor volume (MTV) and total glycolytic activity (TGA) have been proposed as potential prognostic imaging markers for patient outcome in human solid tumors. The purpose of this study was to establish whether MTV and TGA add prognostic information to clinical staging in patients with oral and oropharyngeal squamous cell carcinomas (SCCs). Methods: The Institutional Review Board approved this Health Insurance Portability and Accountability Act–compliant single-institution retrospective study. Forty-five patients with histologically proven oral or oropharyngeal SCC underwent PET/CT for initial cancer staging and were included in the study. MTV was measured using a gradient-based method (PET Edge) and fixed-threshold methods at 38%, 50%, and 60% of maximum standardized uptake value (SUV). The TGA is defined as MTV × mean SUV. Bland–Altman analysis was used to establish the reliability of the methods of segmentation. Outcome endpoints were overall survival (OS) and progression-free survival. Cox proportional hazards univariate and multivariate regression analyses were performed. Results: In Cox regression models, MTV and TGA were the only factors significantly associated with survival outcome after adjusting for all other covariates including American Joint Committee on Cancer (AJCC) stage, with hazards ratio of 1.06 (95% confidence interval, 1.01–1.10; P = 0.006) and 1.00 (95% confidence interval, 1.00–1.01; P = 0.02). The model fit was significantly better when MTV was added to AJCC stage in model I (χ2 value change, 1.16–6.71; P = 0.01) and when TGA was added to AJCC stage in model II (χ2 value change, 1.16–4.37; P = 0.04). The median cutoff point of 7.7 mL for primary tumor MTV was predictive of time to OS (log rank P = 0.04). The median cutoff point of 55 g for PET Edge primary tumor TGA was predictive of time to OS (log rank P = 0.08), though the result was not statistically significant. Conclusion: Gradient-based segmentations of primary tumor MTV and TGA are potential 18F-FDG markers for time to survival in patients with oral and oropharyngeal SCC and may provide prognostic information in addition to AJCC stage. These exploratory imaging markers need validation in larger cohort studies.

PET/CT of Cancer Patients: Part 1, Pancreatic Neoplasms

OBJECTIVE Pancreatic cancer continues to have a poor prognosis despite impressive improvements in the outcomes of many other types of cancer, often because most pancreatic neoplasms are found to be unresectable at diagnosis. The purpose of this review is to provide an overview of pancreatic cancer and the role of modern imaging in its diagnosis and management with an emphasis on (18)F-FDG PET/CT fusion imaging. CONCLUSION Multimodality imaging is critical in the diagnosis and management of pancreatic cancer. PET/CT is increasingly viewed as a useful, accurate, and cost-effective modality in diagnosing and managing pancreatic cancer, but further studies are warranted. Early data suggest that contrast-enhanced PET/CT performed with modern PET/CT scanners yields high-resolution anatomic information for surgical and radiotherapeutic planning and functional information for whole-body staging in the care of patients with this disease.

Fluorodeoxyglucose–Positron-Emission Tomography Imaging of Head and Neck Squamous Cell Cancer

SUMMARY: The hybrid technique of PET/CT has significantly impacted the imaging and management of HNSCC since its introduction in 2001 and has become the technique of choice for imaging of this cancer. Diagnostic FDG-PET/CT is useful for identification of an unknown primary tumor, delineation of extent of primary tumor, detection of regional lymph node involvement even in a normal-sized node, detection of distant metastases and occasional synchronous primary tumor, assessment of therapy response, and long-term surveillance for recurrence and metastases. The role of PET/CT is evolving in radiation therapy planning. Combined diagnostic PET/CT provides the best anatomic and metabolic in vivo information for the comprehensive management of HNSCC.

Value of PET/CT in the Management of Primary Hepatobiliary Tumors, Part 2

OBJECTIVE Primary hepatobiliary malignancies consist of hepatocellular carcinoma, cholangiocarcinoma, and gallbladder cancer. Benign hepatic lesions include hepatic cysts, hemagiomas, adenomas, and focal nodular hyperplasias. The utility of PET/CT in imaging primary hepatobiliary lesions varies according to the type and location of the lesion. CONCLUSION There is a consistent benefit to the use of PET/CT for detection and staging, and it ultimately helps to establish the best course of treatment and to determine prognosis. In addition, PET/CT is very useful in local ablative and systemic therapy assessment and surveillance for hepatobiliary malignancies.

CT Arthrography, MR Arthrography, PET, and Scintigraphy in Osteoarthritis

CT arthrography and MR arthrography are accurate methods for the study of surface cartilage lesions and cartilage loss. They also provide information on subchondral bone and marrow changes, and ligaments and meniscal lesions that can be associated with osteoarthritis. Nuclear medicine also offers new insights in the assessment of the disease. This article discusses the strengths and limitations of CT arthrography and MR arthrography. It also highlights nuclear medicine methods that may be relevant to the study of osteoarthritis in research and clinical practice.

Value of PET/CT in the Management of Liver Metastases, Part 1

OBJECTIVE Metastasis is the most common (95%) of liver lesions. Early diagnosis and staging are the keys to treatment planning and prognosis. There is a consistent benefit to the use of PET/CT for detecting hepatic, local, and distant metastases from a variety of primary malignancies, which can contribute to staging and ultimately helps to establish the best course of treatment and to determine prognosis. CONCLUSION For colorectal cancer, FDG PET and FDG PET/CT are particularly effective for identification of additional hepatic and extrahepatic metastases, frequently upstaging the tumor stage and affecting management. In addition, PET/CT is very useful in local ablative and systemic therapy assessment and surveillance for liver metastases.

PET-Based Primary Tumor Volumetric Parameters and Survival of Patients With Non-Small Cell Lung Carcinoma

OBJECTIVE The purpose of the study was to assess metabolic tumor volume and total glycolytic activity of the primary tumor as prognostic parameters for outcome in patients with non-small cell lung carcinoma (NSCLC). MATERIALS AND METHODS Thirty-nine patients who had undergone a baseline staging PET/CT examination at our institution for the diagnosis of NSCLC were retrospectively identified. The maximum standardized uptake value (SUV(max)), metabolic tumor volume, and total glycolytic activity were segmented from PET using the gradient method; 12-month survival and overall survival at the end of follow-up were used as outcome measures. Multivariate logistic regression, receiver operating characteristic curve analysis, and Kaplan-Meier curves for survival analysis were generated and compared using the Mantel-Cox log-rank test. RESULTS The mean gradient-based metabolic tumor volume and gradient-based total glycolytic activity were significantly greater in the patients who died (93.3 mL and 597.5 g) than in those who survived (19.3 mL and 193.9 g, respectively) (p < 0.003 and p < 0.031). There was no statistically significant difference in the mean SUV(max) between the patients who survived (12.7) at 12 months and those who had died (13.1) (p = 0.85). On multivariate analysis, gradient-based metabolic tumor volume was the only variable associated with 12-month mortality when adjusted for all other factors.(.) The area under the curve (AUC) for gradient-based metabolic tumor volume was 0.77 (p < 0.006). A significant difference in the time to survival was observed between high and low gradient-based metabolic tumor volume (log-rank p < 0.05) cohorts using the median gradient-based metabolic tumor volume (9.7 mL) as the cut point. CONCLUSION PET-based volumetric imaging parameters are potential prognostic markers of outcome in patients with NSCLC.

FDG PET/CT in patients with HIV.

OBJECTIVE This article will discuss the (18)F-FDG normal variant uptake and the role of FDG PET/CT in malignancies in HIV-infected patients, CNS manifestations of HIV, assessing fever of unknown origin in HIV patients, assessing response to highly active antiretroviral therapy and assessing complications. CONCLUSION FDG PET/CT is a valuable imaging study in the management of HIV-infected patients.

Use of 18F-FDG PET/CT as a Predictive Biomarker of Outcome in Patients With Head-and-Neck Non–Squamous Cell Carcinoma

OBJECTIVE The purpose of this article is to establish whether pretreatment (18)F-FDG uptake predicts disease-free survival (DFS) and overall survival in patients with head-and-neck non-squamous cell carcinoma (SCC). MATERIALS AND METHODS Eighteen patients (six women and 12 men; mean [± SD] age at diagnosis, 57.89 ± 13.54 years) with head-and-neck non-SCC were included. Tumor FDG uptake was measured by the maximum standardized uptake value (SUV(max)) and was corrected for background liver FDG uptake to derive the corrected SUV(max). Receiver operating characteristic analyses were used to predict the optimal corrected SUV(max) cutoffs for respective outcomes of DFS (i.e., absence of recurrence) and death. RESULTS The mean corrected SUV(max) of the 18 head-and-neck tumors was 5.63 ± 3.94 (range, 1.14-14.29). The optimal corrected SUV(max) cutoff for predicting DFS and overall survival was 5.79. DFS and overall survival were significantly higher among patients with corrected SUV(max) < 6 than among patients with corrected SUV(max) ≥ 6. The mean DFS for patients with corrected SUV(max) < 6 was 25.7 ± 11.14 months, and the mean DFS for patients with corrected SUV(max) ≥ 6 was 7.88 ± 7.1 months (p < 0.018). Among patients with corrected SUV(max) < 6, none died, and the mean length of follow-up for this group was 35.2 ± 9.96 months. All of the patients who died had corrected SUV(max) ≥ 6, and the overall survival for this group was 13.28 ± 12.89 months (p < 0.001). CONCLUSION FDG uptake, as measured by corrected SUV(max), may be a predictive imaging biomarker for DFS and overall survival in patients with head-and-neck non-SCC.

Parotid Gland Tumors: Preliminary Data for the Value of FDG PET/CT Diagnostic Parameters

OBJECTIVE The purpose of this article is to establish (18)F-FDG metabolic imaging parameters to differentiate benign and malignant tumors of the parotid gland. MATERIALS AND METHODS Forty-nine patients with increased FDG uptake in the parotid gland were selected for the study group (29 men and 20 women; mean age, 63.14 ± 12.32 years). Another 49 patients without head and neck malignancies were selected as the control group (24 men and 25 women; mean age, 65.80 ± 11.51 years); they did not have a parotid lesion or increased FDG uptake in the parotid gland. Maximum standardized uptake value (SUV(max)) was obtained for all patients. Metabolic tumor volume and total glycolytic activity were measured in patients with a discrete parotid lesion (n = 24). Nonparameteric Student t test (Mann-Whitney U test) was performed for between-group analysis. RESULTS The median SUV(max) of the increased diffuse uptake (2.55; interquartile range [IQR], 1.03-4.07) was significantly lower than the median SUV(max) of tumors (8.48; IQR, 1.46-15.5) (p < 0.01). The median SUV(max) of malignant tumors (11.8; IQR, 4.45-19.15) was significantly (p < 0.05) higher than that of benign tumors (6.4; IQR, 3.4-9.0). There was significant difference (p = 0.003) in the median metabolic tumor volume for malignant tumors (8.9; IQR, 5.1-25.5) and benign tumors or lesions (1.4; IQR, 1.00-2.9). Similar results were found for total glycolytic activity for malignant tumors (67.9; IQR, 24.2-137.6) and benign tumors or lesions (8.4; IQR, 3.9-13.6) (p = 0.002). CONCLUSION FDG PET/CT SUV(max), metabolic tumor volume, and total glycolytic activity are imaging parameters to differentiate benign and malignant tumors of the parotid gland.