FDG‑PET/CT for Global Assessment of the Parotid in HIV Patients Using Cocaine



Simi S. Shah

Shah, Simi S1, Mukit, Tahina1, Mouminah, Alaa1, Raynor, William Y2, Werner, Thomas J3, Alavi, Abass3
Faculty / Advisor: Chang, Yu Cheng1
1University of Pennsylvania School of Dental Medicine, Department of Periodontics
2Drexel University College of Medicine, Radiology
3Hospital of the University of Pennsylvania, Radiology

Introduction

Cocaine abuse is associated with several adverse health event, such as xerostomia.In this study, we used 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) to evaluate the inflammation of the parotid gland who has cocaine abused history. The aim of the study is to assess the practicality of using FDG-PET/CT to discern the effects of cocaine on the parotid gland.

Methods

Sixty-four patients were imaged at a single time point and consisted of four different groups: A) HIV patients with cocaine addiction B) HIV patients without cocaine addiction C) HIV negative patients with cocaine addiction D) HIV negative patients without cocaine addiction. One FDG-PET/CT scan was obtained for each patient. Osirix MD software was used to manually delineate the regions of interest (ROIs) containing the left and right parotid glands. The landmarks containing the parotid gland were: the zygomatic arch superiorly, the inferior angle of the mandible inferiorly, and sternocleidomastoid posteriorly. The global mean standardized uptake value (global SUVmean) was calculated in each subject as the average SUV among all voxels contained within the left and right ROIs. Inter-rater reliability was assessed by Pearson correlation. An independent t test and Mann Whitney test were used to determine statistical significance between the independent groups.

Results

Ten subjects were excluded due to imaging issues or unavailability image data. In total, 54 patients were evaluated. Two scatterplots were made, one that excluded subject 58 and one that included subject 58. With the exclusion of subject 58, the inter-rater reliability observed was (r = 0.83). The inclusion of subject 58 lowered the inter-rater reliability (r=0.68) The average global SUVmean of the four groups were: A)1.02 ± 0.69 B)1.43 ± 0.45 C)1.39 ± 0.61 D)1.43 ± 0.65. Boxplots were also made in order to visualize the data. Independent t test revealed no significant differences between the groups. Mann Whitney test also showed some statistically significant differences between groups and demonstrated higher uptake in group B compared to group A (p = 0.03).

Conclusion

A reproducible method with fair inter-rater reliability of evaluating the parotid gland within HIV positive and cocaine addicts was found. Overall, the FDG uptake across all groups was non-significant. Although the HIV patients with cocaine addiction has the lowest FDG uptake. The difference between the groups are not statistically significant difference. Further investigation is necessary to verify the impact of cocaine on Patient who has history of cocaine abused history.