Khaled Alkhawaldeh

Impact of dual-time-point F-18 FDG PET/CT in the assessment of pleural effusion in patients with non-small-cell lung cancer.

Aim: The aim of this study was to assess the utility of dual-time-point F-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) in differentiating benign from malignant pleural disease, in patients with non-small-cell lung cancer. Methods: A total of 61 patients with non-small-cell lung cancer and pleural effusion were included in this retrospective study. All patients had whole-body FDG PET/CT imaging at 60 ± 10 minutes post-FDG injection, whereas 31 patients had second-time delayed imaging repeated at 90 ± 10 minutes for the chest. Maximum standardized uptake values (SUVmax) and the average percent change in SUVmax (%SUV) between time point 1 and time point 2 were calculated. Malignancy was defined using the following criteria: (1) visual assessment using 3-points grading scale; (2) SUVmax ≥2.4; (3) %SUV ≥ +9; and (4) SUVmax ≥2.4 and/or %SUV ≥ +9. Analysis of variance test and receiver operating characteristic analysis were used in statistical analysis. P < 0.05 was considered significant. Results: Follow-up revealed 29 patient with malignant pleural disease and 31 patients with benign pleural effusion. The average SUVmax in malignant effusions was 6.5 ± 4 versus 2.2 ± 0.9 in benign effusions (P < 0.0001). The average %SUV in malignant effusions was +13 ± 10 versus −8 ± 11 in benign effusions (P < 0.0004). Sensitivity, specificity, and accuracy for the 5 criteria were as follows: (1) 86%, 72%, and 79%; (2) 93%, 72%, and 82%; (3) 67%, 94%, and 81%; (4) 100%, 94%, and 97%. Conclusions: Dual-time-point F-18 FDG PET can improve the diagnostic accuracy in differentiating benign from malignant pleural disease, with high sensitivity and good specificity.

Quantitative assessment of FDG uptake in brown fat using standardized uptake value and dual-time-point scanning.

Objectives: Brown fat is a potential source of false-positive findings on FDG PET. The purpose of this study was to show the variability in body distribution of brown fat, the degree of FDG uptake, the changes on dual-time-point scanning, and determine if dual-time-point scanning can help in differentiating brown fat from malignant lesions. Methods: Thirty-two patients were included in this retrospective study (14 male, 18 female, age range: 8–72 years). All patients had hypermetabolic brown fat activity on FDG PET imaging confirmed by computed tomography (CT) scanning. All patients underwent 2 sequential FDG PET scanning (dual-time-point imaging). The average percent change in maximum standardized uptake value (SUVmax) for 120 brown fat spots between time point 1 and time point 2 was calculated. Results: Body distribution of hypermetabolic brown fat in the 32 patients included supraclavicular area (n = 7); cervical and supraclavicular (n = 5); cervical, supraclavicular, and axillae (n = 5); cervical area, supraclavicular, axillae, and paravertebral (n = 8); supraclavicular, cervical, axillae, paravertebral, and mediastinum (n = 4); supraclavicular, cervical, axillae, paravertebral, and upper abdomen (n = 2); and supraclavicular, cervical, axillae, paravertebral, mediastinum, and intercostals (n = 1). SUVmax for brown fat spots ranged from 0.8 to 12.4 and mean SUV was 4.6 + 1.6. On dual-time-point imaging, 91 (76%) of the brown fat spots demonstrated an increase in SUVmax that ranged from 12% to 192% and mean value of 42%, whereas 16 (13%) brown fat spots did not show any change and 11 (11%) spots underwent a drop in SUVmax by 4% to 12%. There was an increase in the number of active brown fat spots in 3 patients on the second time images. Conclusions: Brown fat is a potential source of false positives, which has wide variability in distribution and degree of FDG uptake. On dual-time-point scanning, there is a progressive increase in FDG uptake within most of the hypermetabolic brown fat areas that mimic malignant lesions.

The value of F-18 FDG PET in patients with primary sclerosing cholangitis and cholangiocarcinoma using visual and semiquantitative analysis.

Aim: The aim of this study was to assess the value of 18F-fluorodeoxyglucose positron emission tomography (F-18 FDG PET) in patients with suspected cholangiocarcinoma (CC). Methods: Sixty-five patients with suspected CC were included in this retrospective study. All patients had whole-body FDG PET/CT imaging at a mean time of 100 minutes after administration of FDG injection. PET studies were analyzed using visual analysis and semiquantitative analysis. Semiquantitative analysis was performed using maximum standardized uptake value (SUVmax) and tumor-to-normal liver (T/N) ratio. Malignancy was defined using the following criteria: (1) Visual analysis; (2) SUVmax >3.9; (3) T/N >1.6. Analysis of variance test and receiver operating characteristic analysis were used in statistical analysis. P < 0.05 was considered significant. Results: Follow-up revealed 47 patients with CC. The average SUVmax in CC tumors was 8 ± 2.9 versus 3 ± 1 in benign lesions (P < 0.0001). The average T/N in malignant lesions was 3.5 ± 1.8 versus 1.3 ± 0.4 in benign lesions (P < 0.0001). Sensitivity, specificity, and accuracy for the 3 criteria were as follows: (1) 96%, 67%, and 88%; (2) 94%, 83%, and 91%; (3) 89%, 78%, and 86%. Conclusion: F-18 FDG PET semiquantitative analysis using SUVmax >3.9 as criterion for malignancy could improve the diagnostic accuracy in differentiating malignant from benign lesions in patients with suspected CC.