The impact of multimodality integrated positron emission tomography-computed tomography on improving the staging and management of head and neck malignancy: a cross- sectional study

ABSTRACT BACKGROUND: Clinical assessment of head and neck cancers is highly challenging owing to the complexity of regional anatomy and wide range of lesions. The diagnostic evaluation includes detailed physical examination, biopsy and imaging modalities for disease extent and staging. Appropriate imaging is done to enable determination of precise tumor extent and involvement of lymph nodes, and detection of distant metastases and second primary tumors. OBJECTIVE: To evaluate the initial staging discrepancy between conventional contrasted computed tomography (CT) and 18F-fluorodeoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) and its impact on management plans for head and neck malignancies. DESIGN AND SETTING: Prospective cross-sectional study in two tertiary-level hospitals. METHODS: This study included 30 patients with primary head and neck malignant tumors who underwent contrasted computed tomography and whole-body 18F-FDG PET/CT assessments. The staging and treatment plans were compared with the incremental information obtained after 18F-FDG PET/CT. RESULTS: 18F-FDG PET/CT was found to raise the stage in 33.3% of the cases and the treatment intent was altered in 43.3% of them, while there was no management change in the remaining 56.7%. 18F-FDG PET/CT had higher sensitivity (96% versus 89.2%) and accuracy (93% versus 86.7%) than conventional contrast-enhanced computed tomography. CONCLUSION: Our study demonstrated that 18F-FDG PET/CT had higher sensitivity and accuracy for detecting head and neck malignancy, in comparison with conventional contrast-enhanced computed tomography. 18F-FDG PET/CT improved the initial staging and substantially impacted the management strategy for head and neck malignancies.

Delayed Dual-Time Point Imaging Protocol Improving Myocardial Uptake of 18-Fluorine Flouro Deoxyglucose (18F-FDG) During Viability Screening of Diabetes Mellitus Type 2 Patients Using Integrated Positron Emission Tomography/Computed Tomography (PET/CT) Imaging.

Aims: To investigate the effect of delayed imaging protocol and hypoglycemic agent on quantitative values obtained during myocardial viability 18F-FDG PET/CT assessment. Presentation of Case: Mr. A, a 72 year-old man, Madam B, a 73 year-old woman and Madam C, a 64 year-old woman, presented to the Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia for myocardial viability assessment. All were diagnosed Diabetes Mellitus type II on oral hypoglycemic agent. Discussion: Our study showed an increased 18F-FDG uptake in the wall of LV after the delayed protocol was applied to the patients. One hour time elapsed before 18F-FDG injection is to allow optimal level of niacin in the blood for its action to lower the plasma FFA levels and encourage myocardial preference towards glucose metabolism. Oral glucose loading is given to stimulate insulin secretion and increase glucose utilization as the metabolic substrate. The approach of premedicating nicotinic acid like niacin can be a reliable hypolipidemic agent in shifting myocardial metabolism to glucose oxidative pathway in 18F-FDG PET/CT myocardial viability assessment. Delayed enhancement imaging has been shown to be effective, in both animals and humans, in identifying the presence, location, and extent of acute and chronic myocardial infarction in patients with ischemic cardiomyopathy. Furthermore, this technique may also be useful in assessing myocardial injury in patients with non-ischaemic heart disease. Conclusion: Delayed imaging is superior to early imaging. The improvement of the image quality leads to accurate assessment of the viable or non-viable myocardium.