Variety and complexity of fluorine-18-labelled fluoro-2-deoxy-D-glucose accumulations in the oral cavity of patients with oral cancers

Maximum standardized uptake value in 11C-methionine positron emission tomography may predict the prognosis of patients with oral squamous cell carcinoma

The present study aimed to elucidate the correlation between the uptake of 11C-methionine (MET) by a primary tumor and the survival of patients with oral squamous cell carcinoma (OSCC). This study enrolled 31 patients who underwent radical surgery for OSCC. The patients underwent pretreatment MET-positron emission tomography (PET) scanning. We analyzed correlations between the maximum standardized uptake value (SUVmax) of MET-PET in a primary tumor and the clinicopathological features. Further, we compared overall survival (OS), disease-specific survival (DSS), and loco-regional recurrence (LRR) rates between the two groups according to SUVmax of MET-PET. SUVmax of MET-PET in a primary tumor was higher in patients with advanced T-classification and advanced clinical stage, with significant differences (P = 0.001 and P = 0.016, respectively). The patients with SUVmax of MET-PET ≥ 4.4 showed significantly lower DSS rates and higher LRR rates than those with SUVmax of < 4.4 (P = 0.015 and P = 0.016, respectively). SUVmax of MET-PET and OS rates showed no significant correlation (P = 0.073). The present study revealed that SUVmax of MET-PET may predict clinical outcomes and prognosis in patients with OSCC who underwent radical surgery.

☆Symposium: Imaging modalities for drug-related osteonecrosis of the jaw (5), utility of bone scintigraphy and 18F-FDG PET/CT in early detection and risk assessment of medication-related osteonecrosis of the jaw (secondary publication)

Medication-related osteonecrosis of the jaw (MRONJ) is a significant side effect of antiresorptive and antiangiogenic drugs. Since MRONJ is intractable, early detection is the best way to limit progression. Bone scintigraphy and ¹⁸F- fluorodeoxyglucose positron-emission tomography can detect minimal and subclinical changes in bones earlier than conventional radiological modalities. A differential diagnosis including MRONJ is recommended when abnormally high uptakes are incidentally detected in the jaws of patients who have bone metastases. Quantitative analysis of uptakes, such as bone scan index of the jaw using neural network analysis and maximum standardized uptake value, could differentiate MRONJ from common dental diseases and be useful for the early detection and risk assessment of MRONJ.

Changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose accumulation into tongue-related muscles after dissection in patients with tongue cancer

OBJECTIVES

To elucidate the changes in the distributions of fluorine-18-labelled fluoro-2-deoxy-d-glucose (¹⁸F-FDG) accumulation in the tongue muscles of patients following four kinds of surgical operations for tongue cancers.

METHODS

The changes in the distributions of ¹⁸F-FDG accumulations in the tongue muscles on positron emission tomography (PET)-CT, in association with imaging findings on CT and MRI, were retrospectively analyzed before and after four kinds of surgical operations for 50 patients with tongue cancers.

RESULTS

¹⁸F-FDG-PET-positive areas appeared at the back of the intrinsic muscles of the tongue after invasive surgery for tongue cancers despite the absence of abnormal findings on CT and MRI. A correlation between the standardized uptake value maximum of ¹⁸F-FDG in the intrinsic muscles and the degree of invasiveness of the surgical procedures for tongue cancers (r = 0.539, p < 0.01) was found.

CONCLUSIONS

It is important to pay attention to the changes in ¹⁸F-FDG distributions in the intrinsic muscles of the tongue before and after invasive surgery despite the absence of abnormal findings on CT and MRI when evaluating the tongue on ¹⁸F-FDG-PET.

Alterations in 18F-FDG accumulation into neck-related muscles after neck dissection for patients with oral cancers

BACKGROUND

18F-fluoro-2-deoxy-D-glucose (18F-FDG) accumulations are commonly seen in the neck-related muscles of the surgical and non-surgical sides after surgery with neck dissection (ND) for oral cancers, which leads to radiologists having difficulty in diagnosing the lesions. To examine the alterations in 18F-FDG accumulation in neck-related muscles of patients after ND for oral cancer.

MATERIAL AND METHODS

18F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) in neck-related muscles were retrospectively analyzed after surgical dissection of cervical lymph nodes in oral cancers.

RESULTS

According to the extent of ND of cervical lymph nodes, the rate of patients with 18F-FDG-PET-positive areas increased in the trapezius, sternocleidomastoid, and posterior neck muscles of the surgical and/or non-surgical sides. In addition, SUVmax of 18F-FDG-PET-positive areas in the trapezius and sternocleidomastoid muscles were increased according to the extent of the ND.

CONCLUSIONS

In evaluating 18F-FDG accumulations after ND for oral cancers, we should pay attention to the 18F-FDG distributions in neck-related muscles including the non-surgical side as false-positive findings.