The value of 18F-fluoride PET/CT in the assessment of screw loosening in patients after intervertebral fusion stabilization

The Use of 18F-Fluoride Positron Emission Tomography/Computed Tomography Scanning to Identify Sources of Pain after Posterior Lumbar Interbody Fusion-An Analysis in Patients with and without Symptoms

BACKGROUND

Identifying the cause of recurrent or persisting pain after posterior lumbar interbody fusion (PLIF) is essential for establishing optimal treatment. In this study, we evaluate patients after PLIF surgery by 18F-fluoride PET/CT scans and patient-reported outcome measures (PROMs).

METHODS

A total of 36 PLIF patients were included. Sixty minutes after intravenous injection of 18F-fluoride, PET/CT scanning was performed. Bone graft ingrowth, subsidence, screw loosening and damage of facet joints were scored by quantifying the level of bone metabolism of the vertebral endplates in the disc spaces, around screws and around the facet joints on the PET scans.

RESULTS

In contrast to asymptomatic patients, symptomatic patients showed abnormal PET values around pedicle screws and/or facet joints and at the lower endplates of the disc spaces, identifying a possible source of pain. On CT, no significant differences between these two groups were found.

CONCLUSION

The PET/CT findings appeared to correlate better with symptoms on PROMs compared to CT findings alone. When interpreting 18F-fluoride PET/CT findings after PLIF surgery, one should realize bone metabolism in the disc spaces of the operated segments and around pedicle screws or facet joint changes during follow-up, reflecting natural recovery.

SPECT/CT and PET/CT for the Evaluation of Persistent or Recurrent Pain After Spine Surgery: A Systematic Review and Case Series

OBJECTIVE

The differential diagnosis for postoperative back pain is broad, and conventional imaging modalities are not always conclusive. Therefore, we performed a systematic review of the literature and present case studies describing the use of single-photon emission CT (SPECT)/CT or positron emission tomography (PET)/CT in the diagnosis of back pain following spine surgery.

METHODS

A systematic review was conducted according to PRISMA guidelines across 5 databases. Relevant keywords included PET/CT, bone SPECT/CT, and pseudarthrosis. The studies were assessed for diagnostic accuracy of the imaging technologies.

RESULTS

A total of 2,444 studies were screened, 91 were selected for full-text review, and 21 were ultimately included. Six retrospective studies investigated the use of SPECT/CT with a total sample size of 309 patients. Two of these studies used SPECT/CT to predict screw loosening in over 50% of patients. Eight studies examined the use of 18-fluoride sodium fluoride (18F-NaF) PET/CT. Among these studies, measures of diagnostic accuracy varied but overall demonstrated the ability of 18F-NaF PET/CT to detect screw loosening and pseudarthrosis. Seven studies examined 18F-fluorodeoxyglucose (FDG) PET/CT and supported its utility in the diagnosis of postoperative infections in the spine.

CONCLUSIONS

PET/CT and SPECT/CT are useful in the evaluation of postoperative pain of the spine, especially in patients for whom conventional imaging modalities yield inconclusive results. More diagnostic accuracy studies with strong reference standards are needed to compare hybrid imaging to conventional imaging.

Using 68 Ga-DOTATATE PET for Postoperative Radiosurgery and Radiotherapy Planning in Patients With Meningioma: A Case Series

BACKGROUND

For patients with either an incompletely resected meningioma or recurrence after surgery, stereotactic radiosurgery is frequently used. MRI is typically used for stereotactic radiosurgery targeting, but differentiating tumor growth from postoperative change can be challenging. 68 Ga-DOTATATE, a positron emission tomography (PET) radiotracer targeting the somatostatin receptor type 2, has been shown to be a reliable meningioma biomarker.

OBJECTIVE

To evaluate the impact of 68 Ga-DOTATATE on treatment planning in patients who had previously undergone meningioma resection.

METHODS

We present a consecutive case series of 12 patients with pathology-proven meningioma who received a 68 Ga-DOTATATE PET between April 2019 and April 2021. Treatment planning was performed first using MRI. DOTATATE-PET images were then used to assess accurate tumor identification.

RESULTS

Ten patients had WHO Grade 2 meningioma, and 2 patients had Grade 1 tumor. Eight patients had recurrent meningiomas, and 4 patients had newly diagnosed disease. Overall, 68 Ga-DOTATATE PET scans altered previously formulated treatment plans in 5 of 12 patients. In addition, 9 of 12 patients had disease foci not appreciated on MRI.

CONCLUSION

In this series, incorporating 68 Ga-DOTATATE PET imaging had clinical utility for most patients in whom it was used. It proved particularly adept in demonstrating intraosseous meningiomas, differentiating recurrence from postoperative changes, and identifying subcentimeter disease foci. It is an imaging modality that our center will continue to use as a means of improving postoperative treatment plans after the surgical resection of meningiomas.

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.

Total-Body PET Imaging of Musculoskeletal Disorders

Imaging of musculoskeletal disorders, including arthritis, infection, osteoporosis, sarcopenia, and malignancies, is often limited when using conventional modalities such as radiography, computed tomography (CT), and MR imaging. As a result of recent advances in Positron Emission Tomography (PET) instrumentation, total-body PET/CT offers a longer axial field-of-view, higher geometric sensitivity, and higher spatial resolution compared with standard PET systems. This article discusses the potential applications of total-body PET/CT imaging in the assessment of musculoskeletal disorders.

Role of 18F-flurodeoxyglucose in orthopaedic implant-related infection: review of literature and experience

Infection and inflammation are a common occurrence with orthopaedic procedures. Anatomical modalities can show the transformation in the disease process; however, these may occur later when compared with functional imaging modalities that are more likely to identify early disease patterns. Various molecular imaging modalities such as three-phase bone scintigraphy, labelled leucocyte scintigraphy, as well as radiolabelled antibiotics and immunoglobulins have been considered and have played key roles in assisting clinical decision-making. While 18F-flurodeoxyglucose (FDG) PET/computed tomography (CT) has been relatively well established in cancer pathways, it has the potential to contribute to surgical decision making for possible osteomyelitis post-metal implant surgery. In this article, we present a review of recently used tracers, and share our experience with using 18F-FDG PET/CT studies in a few diverse clinical settings related to post-metal implant osteomyelitis.