Unsuspected Metastatic Ovarian Cancer Revealed by 18F-NaF PET/CT Performed to Evaluate Lower-Back Pain

Novel Musculoskeletal and Orthopedic Applications of 18F-Sodium Fluoride PET

PET imaging with ¹⁸F-sodium fluoride (NaF), combined with computed tomography or magnetic resonance, is a sensitive method of assessing bone turnover. Although NaF-PET is gaining popularity in detecting prostate cancer metastases to bone marrow, osseous changes represent secondary effects of cancer cell growth. PET tracers more appropriate for assessing prostate cancer metastases directly portray malignant activity and include ¹⁸F-fluciclovine and prostatic specific membrane antigen ligands. Recent studies investigating NaF-PET suggest utility in the assessment of benign musculoskeletal disorders. Emerging applications in assessing traumatic injuries, joint disease, back pain, orthopedic complications, and metabolic bone disease are discussed.

18F-NaF Uptake in Breast Cancer

A 55-year-old woman with back pain underwent F-NaF PET/CT study to evaluate bone metastases from newly diagnosed breast cancer. Multiple foci of increased tracer uptake indicating osteoblastic metastases were noted in cervical and thoracic vertebrae. Unexpectedly, breast cancer also revealed increased NaF activity.

18F-NaF Uptake in Retroperitoneal Neurofibroma and Uterine Leiomyoma Calcifications

A 48-year-old woman with intermittent lower back pain for 9 months and known retroperitoneal neurofibroma underwent F-NaF PET/CT scan to assess possible bony lesions causing the pain. Incidentally, the images showed elevated NaF activity in the retroperitoneal neurofibroma. In addition, uterine leiomyoma with heterogeneous calcifications revealed increased NaF activity.

18F-NaF Uptake in Ocular Prosthesis (Implant)

Ocular prosthesis is used as a replacement in the orbit following enucleation or evisceration of the eye. Polymethyl methacrylate (PMMA), hydroxyapatite (HA) and porous polyethylene (PP) are some examples of the materials used in ocular prosthesis. We present a case of an 82-year-old man with prostate cancer who underwent F-NaF PET/CT imaging for evaluation of bone metastases and was incidentally found to have increased NaF uptake in the ocular prosthesis.

Identification of Heterotopic Ossification Using 18F-NaF PET/CT

Heterotopic ossification (HO) is a benign condition characterized by the abnormal formation of mature lamellar bone in extraskeletal soft tissues. Most frequently, HO is observed around the hip joint after fractures or surgical procedures such as open reduction internal fixation or total hip arthroplasties. We are presenting a case of HO as detected by F-NaF PET/CT in a 68-year-old woman with multiple myeloma and a history of internal fixation of the right hip. Many previous publications have reported F-NaF uptake portraying calcification in soft tissue; the present report demonstrates the feasibility of F-NaF PET/CT to assess extraosseous calcification.

The Detection of Uterine Leiomyoma (Fibroid) Calcifications on 18F-NaF PET/CT

Uterine leiomyomas (fibroids) are the most common type of uterine neoplasms in premenopausal women. Leiomyomas are estrogen dependent and tend to atrophy and shrink in size after menopause. Dystrophic calcification, cystic changes, and necrosis are among the changes that indicate uterine fibroid involution. We are presenting a calcified uterine leiomyoma in a 61-year-old woman as incidentally detected on F-NaF PET/CT scanning. Many previous publications have reported the accumulation of F-NaF in soft tissue calcifications; these findings further set new directions in the evaluation of the metabolic activity of macrocalcification and microcalcification using molecular imaging probes.