Significant 99mTc-MDP but Unimpressive 18F-NaF Gastric Activity in a Patient With Multiple Myeloma

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.

The clinical significance of incidental soft tissue uptake on whole body 18F-sodium fluoride bone PET-CT

¹⁸F-sodium fluoride (NaF) is a PET bone imaging agent and is commonly used in imaging patients with cancer; however, similar to technetium-99m medronic acid (^99mTc-MDP), it can be useful in the evaluation of benign bone and joint conditions. NaF is an excellent bone-seeking agent with high bone uptake due to rapid single-pass extraction. It has negligible plasma protein binding, rapid blood, renal clearance, high bone uptake and almost all NaF delivered is retained by bone after a single pass of blood; however, uptake of NaF can be observed in non-osseous structures such as the arterial vasculature, gastrointestinal tract, genitourinary tract, and viscera. In this article, we present a spectrum of clinical cases with non-osseous NaF uptake in patients referred for cancer staging.

Discordant Findings on 18F-NaF and 99mTc-HDP Bone Scans in a Patient With ATTR Cardiac Amyloidosis

Cardiac amyloidosis is an important cause of restrictive cardiomyopathy and congestive heart failure. Bone scintigraphy with [Tc]hydroxymethylene diphosphonate (Tc-HDP) and [F]sodium fluoride (F-NaF) have been investigated in the noninvasive diagnosis of transthyretin (ATTR)-related cardiac amyloidosis. We present a case of a 76-year-old man with metastatic prostate cancer who underwent Tc-HDP bone scintigraphy with an incidental finding of diffuse left ventricular abnormal uptake suggesting ATTR cardiac amyloidosis. Review of previous imaging showed a negative F-NaF PET/CT study. This example suggests that the mechanism of uptake of Tc-HDP and F-NaF may differ in patients with ATTR cardiac amyloidosis.

Is 99m Tc-methylene diphosphonate bone scintigraphy a sensitive method for detecting bone lesions in multiple myeloma?

Background

Bone lesion in multiple myeloma (MM) is most commonly presented as a lytic lesion in this disease. Determination of extent of bone lesions in MM is necessary to follow-up the patients. Whole body bone scan with 99m, Tc-methylene diphosphonate (MDP) has a lower sensitivity than other modalities.

Methods

From the patients with MM admitted to Ayatollah Rouhani Hospital of Babol-Iran from 2009 to 2015, who had undergone whole body bone scan during diagnostic process, were entered into the study. Findings of bone scan were compared with MRI.

Results

Of the 19 patients, sixteen (84.2%) of them had positive finding in bone scan, fifteen (78.9%) had MRI of the spine. While of the thirteen patients who had positive finding in MRI, seven (53.8%) had more positive finding in thorcolumbosacral MRI than in bone scan.

Conclusions

99m-Tc MDP bone scan is a sensitive but insufficient method for detecting bone lesions in MM.