F-18 FDG PET/CT Following Dental Extraction in a Patient With Head and Neck Cancer

Primary Intraosseous Squamous Cell Carcinoma of the Mandible Mimicking Inflammation on FDG PET/CT

ABSTRACT

Primary intraosseous squamous cell carcinoma (SCC) is an uncommon malignant cancer involving the jaw bones. We herein reported the imaging findings of a primary intraosseous SCC of the mandible in a 47-year-old man. He was diagnosed as cancer of unknown primary in the cervical node. FDG PET/CT revealed a focal hypermetabolic lesion around the tooth root of the right lower molar. MRI showed the lesion had hyperintensity on T2-weighted imaging and significant enhancement on T1-weighted imaging fat saturate images. The final diagnosis of primary intraosseous SCC of mandible was confirmed pathologically.

Reflection of ¹⁸F-FDG accumulation in the evaluation of the extent of periapical or periodontal inflammation

OBJECTIVES

To elucidate whether fluorine-18-labeled ((18)F) fluoro-2-deoxy-d-glucose (FDG) accumulation can reflect the extent of periodontal inflammation, periapical inflammation, or dental caries.

STUDY DESIGN

(18)F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) were retrospectively compared with the size of the bone resorption areas caused by periodontal inflammation, periapical inflammation, or dental caries on panoramic radiographs, CT, and magnetic resonance imaging (MRI) in 44 subjects.

RESULTS

A significant correlation was found between the size of the bone resorption area caused by periodontal (r = 0.595, P < .01) or periapical (r = 0.560, P < .01) inflammation and the highest standardized uptake value (SUVmax) of (18)F-FDG accumulation. A significant correlation was found between the periodontal (r = 0.622, P < .01) or periapical (r = 0.394, P < .01) inflammatory findings on MRI and the SUVmax of (18)F-FDG accumulation. The SUVmax of (18)F-FDG around most teeth with caries was under 1.5.

CONCLUSIONS

(18)F-FDG accumulation reflects the extent of dental inflammation, not dental caries.

Measuring the "unmeasurable": assessment of bone marrow response to therapy using FDG-PET in patients with lymphoma

RATIONALE AND OBJECTIVES

To determine if anatomically "nonmeasurable" disease in bone marrow (BM) is assessable for response to therapy by [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT).

MATERIALS AND METHODS

FDG PET/CT images of 27 patients with lymphoma, FDG-avid bone marrow (BM) lesions, and >or=1 FDG-avid, tumor-involved lymph node (LN) at baseline were retrospectively reviewed. FDG uptake in target LNs and BM foci was determined pre- and posttherapy using the standardized uptake value corrected for lean body mass (SUL(mean)). Size of the same target LNs was measured pre- and posttherapy on CT. Percentage decreases of LN size and LN and BM SUL were calculated. Response was classified according to revised International Workshop Criteria (IWC) with and without modification for metabolic evaluation of BM and correlated to overall survival. Statistical analyses were performed using paired t-tests, Pearson correlation coefficients, and z-tests.

RESULTS

LN size, LN SUL(mean), and BM SUL(mean) were significantly higher pre- versus posttherapy (2337 mm(2) +/- 1810 vs. 309 mm(2) +/- 323; 6.94 +/- 4.96 vs. 1.02 +/- 1.00; and 6.81 +/- 4.58 to 1.84 +/- 1.58, all P < .001, respectively). After therapy, significant correlation was found between percentage declines of LN size and SUL(mean) of LNs (r = 0.84, P < .001) or BM (r = 0.56, P = .002) and SUL(mean) of LN and BM (r = 0.76, P < .001). Including a metabolic assessment of BM correctly altered overall response assessment in 5/27 (19%) patients and better predicted overall survival than revised IWC.

CONCLUSION

Anatomically "unmeasurable" BM infiltration with lymphoma behaves similarly to LN disease after therapy and is "measurable" by FDG PET/CT. FDG PET/CT is valuable for monitoring tumor response in "measurable" disease and BM, which was previously considered "unmeasurable" by anatomical imaging.