Primary pain generator identification by CT-SPECT in patients with degenerative spinal disease

A Comparison of Magnetic Resonance Imaging and SPECT-CT Imaging in Complex Spine Pathology: Does SPECT-CT Provide Additional Diagnostic Information Over Magnetic Resonance Imaging?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Magnetic Resonance Imaging (MRI) is often regarded as the gold standard for spinal pathology, as it provides good structural visualisation. SPECT-CT, however, provides combined structural and functional information. There is a paucity of literature comparing SPECT-CT with MRI in the spine. Our aim was to determine whether SPECT-CT provides additional information to MRI in individuals with complex spinal pathology, including deformity, which altered management.

METHODS

We conducted a retrospective review of all individuals seen at our tertiary spinal unit that were investigated with both MRI and SPECT-CT of the spine between 2007-2020. We reviewed imaging reports, and collated diagnoses, surgical treatment and the relative contributions of MRI and SPECT-CT to management decisions.

RESULTS

104 individuals identified, with a mean age of 30 years (89 females and 15 males). Diagnostic categories were adolescent, adult, and congenital deformity, degenerative pathology, and miscellaneous pathology. MRI returned positive findings in 58 (55.8%), and SPECT-CT in 41 (39.4%) cases. SPECT-CT identified 10 cases of facet joint degeneration, 5 of increased uptake around metalwork suggestive of loosening, 1 pseudoarthrosis, 1 partial failure of fusion and 1 osteoid osteoma which were not reported on MRI, all in individuals who had previously undergone spinal instrumentation. Despite this, SPECT-CT only altered management for 6 individuals (5.8%).

CONCLUSION

MRI is less useful in the setting of previous instrumentation due to metal artefact. Where MRI is inconclusive, particularly in individuals with previous spinal instrumentation, SPECT-CT may provide a diagnosis, but is not recommended as primary imaging.

Biomechanical Predictors of Sacroiliac Joint Uptake on Single-Photon Emission Computed Tomography/Computed Tomography

OBJECTIVE

Single-photon emission computed tomography/computed tomography (SPECT/CT) is an emerging imaging modality that identifies sites of heightened bone metabolism in response to increased stresses. The relationship between sacroiliac (SI) joint radiotracer uptake and anatomic biomechanical parameters is poorly understood.

METHODS

Adult patients with SPECT/CT scans performed at our institution between 2021 and 2023 for the workup of low back pain were included. Patient charts were reviewed for demographic factors including age, gender, and prior thoracolumbar fusion history. Biomechanical spinopelvic parameters were measured from standing scoliosis radiographs. SPECT/CT scans were reviewed for uptake at the SI joint. Patients were stratified into 2 cohorts; patients with SI uptake greater than iliac crest uptake were designated "hot," whereas those with less or equal uptake were labeled "cold."

RESULTS

One-hundred and sixty patients met inclusion criteria. Patients were slightly more male (55%) with average age 55 ± 14.9 years. Sixty-eight patients (43%) had evidence of increased SI activity. Interrater reliability showed substantial agreement (kappa = 0.62). The hot cohort demonstrated greater pelvic incidence (54.8 ± 14.0 degrees vs. 51.0 ± 11.0 degrees, P = 0.031) and pelvic tilt (20.8 ± 9.5 degrees vs. 18.4 ± 8.6 degrees, P =0.047) compared with the cold cohort. Patients were otherwise similar between cohorts (P > 0.05).

CONCLUSIONS

Increased pelvic incidence and pelvic tilt angles are associated with SPECT/CT uptake at the SI joint, which may reflect altered biomechanics at the spinopelvic junction. SPECT/CT may be a valuable tool to assess SI degeneration. Future studies are warranted to better characterize the clinical applications of these findings.

Coronal Deformity is Associated With Uptake on Single Photon Emission Computed Tomography in Patients With Low Back Pain

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) is emerging as a valuable imaging test for identifying pain generators within the lumbar spine. The relationship between radiotracer uptake on SPECT/CT and anatomic biomechanical parameters has not been previously studied.

METHODS

We performed a retrospective review of all patients seen at our institution between 2021-2023 who obtained SPECT/CT scans for workup of thoracolumbar back pain. Patient data including demographic, clinical symptoms, and surgical history were collected. Radiology reports were reviewed for evidence of pathologic degeneration and increased bone metabolism on SPECT/CT. Biomechanical parameters were measured from standing scoliosis plain radiographs. Patients were stratified into two cohorts by either presence or absence of asymmetric coronal uptake on SPECT/CT.

RESULTS

160 patients met inclusion criteria. Patients were primarily male (55%) with average age 55 ± 15 years. 87 (54%) patients demonstrated asymmetric uptake on SPECT/CT. These patients were older (P < 0.001), but with similar gender, prior fusion history, sacroiliitis, adjacent segment degeneration, and pseudoarthrosis (P > 0.05). This cohort had more disc disease, facet arthropathy, and greater degree of coronal scoliosis and coronal imbalance (P < 0.001). There were significantly more sites of uptake in the asymmetric cohort, and uptake was preferentially observed in the concavity of the lumbar curve (P < 0.001). There were no significant differences in sagittal balance or spinopelvic mismatch between cohorts (P > 0.05).

CONCLUSION

Asymmetric uptake on SPECT/CT was associated with coronal deformity in patients with low back pain. Further prospective studies are warranted to assess the effect of coronal deformity on pain generation.

Single-Photon Emission Computed Tomography (SPECT-CT) as a Predictor of Pain Generators in Patients Undergoing Anterior Cervical Discectomy and Fusion (ACDF) for Axial Cervical Pain

BACKGROUND

Axial neck pain is often associated with cervical instability, and surgical options are often reserved for patients with either neurological compromise or deformity of the spine. However, cervical facet arthropathy is often implicated with instability and the location of painful generators is often difficult to ascertain. Single-photon emission computed tomography (SPECT-CT) presents an adjunct to conventional imaging in the workup of patients with suspected facetogenic pain. We aimed to report our experience with patients undergoing anterior cervical discectomy and fusion (ACDF) guided by SPECT-CT for axial cervical pain.

METHODS

We retrospectively identified all cases undergoing ACDF that presented with axial neck pain where correlating SPECT-CT high metabolism areas were identified. Patients were treated at a tertiary care institution between January 2018 and January 2021. Patients with positive radiotracer uptake pre-operatively were compared with patients undergoing ACDF without uptake on SPECT-CT. The pre- and post-operative patients who reported neck pain at one year were compared.

RESULTS

Thirty-five patients were included in this retrospective cohort. The median pre- and post-intervention (at one-year follow-up) visual analog score (VAS) of patients undergoing ACDF without uptake on SPECT-CT was 7 and 3 (p<0.01), while the pre- and post-VAS for patients undergoing surgery with positive uptake on SPECT-CT was 8.5 and 0 (p<0.01). Improvement was significantly larger for patients undergoing SPECT-CT-guided ACDF (p=0.02). At one year after surgery, none of the assessed patients required additional surgical intervention.

CONCLUSION

This case series represents the experience of our group to date with patients undergoing SPECT-CT-guided ACDF with results suggesting potential benefit in guiding fusion.

Correlating SPECT-CT activity in cervical facet joints with positive response to cervical medial branch blocks

Introduction

Cervical facet arthritis is a significant source of neck pain and impaired function that is amenable to treatment with medial branch radiofrequency neurotomy (RFN). Identifying appropriate patients for this treatment requires integration of information from the history, physical exam and diagnostic imaging, but the current diagnostic standard for facet-mediated pain is positive comparative medial branch blockade (MBB). SPECT-CT has recently been evaluated as a potential predictor of positive medial branch blocks with mixed results. The purpose of this retrospective analysis was to determine if a relationship exists between increased uptake on SPECT-CT of a given cervical facet joint and a positive MBB.

Methods

A retrospective review was performed to identify all patients undergoing cervical MBB within 12 months after having a cervical SPECT-CT. Each procedure was categorized as either Concordant (all facet joints demonstrating increased 99mTc uptake on SPECT-CT were blocked) or Discordant (at least one facet joint demonstrating increased 99mTc uptake on SPECT-CT was not blocked or block was performed in a patient that had no increased uptake on SPECT-CT). Statistical analysis was performed to determine if concordance between facet joints demonstrating increased uptake on SPECT-CT and those undergoing MBB was associated with a positive block using cutoffs of 50% and 80% pain relief.

Results

A total of 43 procedures were analyzed (25% Concordant, 75% Discordant) and both groups demonstrated improvement in pain Numeric Rating Scale (NRS) scores. No significant association between concordance and positive MBB was identified at thresholds of 50% (p = .481) and 80% (p = 1.000) pain relief.

Conclusion

SPECT-CT findings do not accurately predict positive cervical MBB but may provide valuable information that can be considered with other factors when deciding which joints to treat.

Correlating SPECT-CT activity in lumbar facet joints with response to lumbar medial branch and L5 dorsal ramus blocks

Introduction

Lumbar facet arthritis is a significant source of back pain and impaired function that is amenable to treatment with medial branch radiofrequency neurotomy (RFN). Identifying appropriate patients for this treatment requires integration of information from the history, physical exam, and diagnostic imaging, but the current diagnostic standard for facet-mediated pain is positive comparative medial branch blocks (MBBs). Lumbar SPECT-CT has recently been evaluated as a potential predictor of positive MBBs with mixed results. The purpose of this retrospective analysis was to determine if the level of concordance between SPECT-CT uptake and facet joints targeted with MBB was associated with a positive block.

Methods

A retrospective review was performed to identify all patients undergoing lumbar MBB within 12 months after having a lumbar SPECT-CT. Each procedure was classified into one of four categories based on the level of concordance between facet joints demonstrating increased 99mTc uptake on SPECT-CT and those being blocked: 1) Complete Concordance (all joints demonstrating increased uptake were blocked and no additional joints blocked); 2) Partial Concordance (all joints demonstrating increased uptake were blocked, with at least one joint not demonstrating increased uptake blocked); 3) Partial Discordance (at least one but not all joints demonstrating increased uptake were blocked); 4) Complete Discordance (all blocks performed at joints not demonstrating increased uptake). Statistical analysis was performed to determine if the level of concordance between increased uptake on SPECT-CT and joints undergoing MBB was associated with a positive block using cutoffs of 50 % and 80 % pain relief.

Results

A total of 180 procedures were analyzed (23 % Complete Concordance, 22 % Partial Concordance, 31 % Partial Discordance, 24 % Complete Discordance) and all groups demonstrated improvement in pain Numeric Rating Scale (NRS) scores. There was no significant association between level of concordance and having a positive block using thresholds of 50 % pain relief, χ 2(3, N = 180) = 4.880, p = .181; or 80 % pain relief, χ 2(3, N = 180) = 1.272, p = .736.

Conclusion

SPECT-CT findings do not accurately predict positive lumbar MBB but may provide valuable information that can be considered with other factors when deciding which joints to treat.

Radiotracers in the Diagnosis of Pain: A Mini Review

The diagnosis and understanding of pain is challenging in clinical practice. Assessing pain relies heavily on self-reporting by patients, rendering it inherently subjective. Traditional clinical imaging methods such as computed tomography and magnetic resonance imaging can only detect anatomical abnormalities, offering limited sensitivity and specificity in identifying pain-causing conditions. Radiotracers play a vital role in molecular imaging that aims to identify abnormal biological processes at the cellular level, even in apparently normal anatomical structures. Therefore, molecular imaging is an important area of research as a prospective diagnostic modality for pain-causing pathophysiology. We present a mini review of the current knowledge base regarding radiotracers for identification of pain in vivo. We also describe radiocaine, a novel positron emission tomography imaging agent for sodium channels that has shown great potential for identifying/labeling pain-producing nerves and producing an objectively measurable pain intensity signal.

SPECT/CT Scan: A New Diagnostic Tool in Pain Medicine

PURPOSE OF REVIEW

The purpose of this review is to evaluate the role of SPECT/CT in identifying facet joint arthropathy and the outcomes of interventions with SPECT/CT as an adjunct.

RECENT FINDINGS

A positive finding of facet arthropathy on SPECT/CT is associated with a higher likelihood of a unilateral procedure and a significantly more effective intervention compared with those performed on patients with facet arthropathy diagnosed only by clinical and/or radiologic examination. Surgical treatment of SPECT/CT-positive findings appears to have a good effect; however, due to limitations in the available studies, no strong conclusion can be drawn. SPECT/CT has a good correlation identifying pain generators in chronic neck and back pain. SPECT/CT-targeted facet interventions demonstrate a higher success rate, but SPECT/CT is not recommended as a first-line diagnostic tool prior to diagnostic facet interventions. More robust studies are needed to confirm the higher success of surgical treatment for SPECT/CT-positive facet arthropathy.

Spinal fusion for single-level SPECT/CT positive lumbar degenerative disc disease: the SPINUS I study

INTRODUCTION AND PURPOSE

With current imaging modalities and diagnostic tests, identifying pain generators in patients with non-specific chronic low back pain (CLBP) is difficult. There is growing evidence of the effectiveness of SPECT/CT examination in diagnosing the source of pain in the spine. The study aims to investigate the effect of posterior interbody fusion on a single-level SPECT/CT positive lumbar degenerative disc disease (DDD).

MATERIAL AND METHODS

This is a prospective study of patients with chronic low back pain (CLBP) operated on for a single-level SPECT/CT positive DDD. Primary outcomes were changes in visual analogue scale (VAS) scores and the Oswestry Disability Index (ODI). Secondary outcomes were complications, return to work, satisfaction and willingness to re-undergo surgery.

RESULTS

During a 3-year period, 38 patients underwent single-level fusion surgery. The mean preoperative VAS score of 8.4 (± 1.1) decreased to 3.2 (± 2.5, p < 0.001) and the mean preoperative ODI of 51.5 (± 7.3) improved to 20.7 (± 14.68, p < 0.001) at a 2-year follow-up. A minimum clinically important difference (30% reduction in VAS and ODI) was achieved in 84.2% of patients. Some 71% of patients were satisfied with the surgery results and 89.4% would undergo surgery again. There were four complications, and two patients underwent revision surgery. Some 82.9% of patients returned to work.

CONCLUSION

Fusion for one-level SPECT/CT positive lumbar DDD resulted in substantial clinical improvement and satisfaction with surgical treatment. Therefore, SPECT/CT imaging could be useful in assessing patients with CLBP, especially those with unclear MRI findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04876586.

Delphi-Based Expert Consensus Statements for the Management of Percutaneous Radiofrequency Neurotomy in the Treatment of Lumbar Facet Joint Syndrome

INTRODUCTION

A modified Delphi strategy was implemented for obtaining recommendations that could be useful in the management of percutaneous radiofrequency treatment of lumbar facet joint syndrome, as the literature on the argument was poor in quality.

METHODS

An Italian research team conducted a comprehensive literature search, defined the investigation topics (diagnosis, treatment, and outcome evaluation), and developed an explorative semi-structured questionnaire. They also selected the members of the panel. After an online meeting with the participants, the board developed a structured questionnaire of 15 closed statements (round 1). A five-point Likert scale was used and the cut-off for consensus was established at a minimum of 70% of the number of respondents (level of agreement ≥ 4, agree or strongly agree). The statements without consensus were rephrased (round 2).

RESULTS

Forty-one clinicians were included in the panel and responded in both rounds. After the first round, consensus (≥ 70%) was obtained in 9 out of 15 statements. In the second round, only one out of six statements reached the threshold. The lack of consensus was observed for statements concerning the use of imaging for a diagnosis [54%, median 4, interquartile range (IQR) 3-5], number of diagnostic blocks (37%, median 4, IQR 2-4), bilateral denervation (59%, median 4, IQR 2-4), technique and number of lesions (66%, median 4, IQR 3-5), and strategy after denervation failure (68%, median 4, IQR 3-4).

CONCLUSION

Results of the Delphi investigations suggest that there is a need to define standardized protocols to address this clinical problem. This step is essential for designing high-quality studies and filling current gaps in scientific evidence.

Role of Single-Photon Emission Computed Tomography Imaging in the Diagnosis and Treatment of Chronic Neck or Back Pain Caused by Spinal Degeneration: A Systematic Review

BACKGROUND

Chronic neck or back pain is a common clinical problem. The most likely cause is degenerative change, whereas other causes are relatively rare. There is increasing evidence on using hybrid single-photon emission computed tomography (SPECT) to identify the pain generator in spine degeneration. This systematic review explores the diagnostic and therapeutic evidence on chronic neck or back pain examined by SPECT.

METHODS

This review is reported in accordance with the PRISMA guidelines. In October 2022, we searched the following sources: MEDLINE, Embase, CINAHL, SCOPUS, and 3 other sources. Titles and abstracts were screened and classified into diagnostic studies, facet block studies, and surgical studies. We synthesized the results narratively.

RESULTS

The search yielded 2347 records. We identified 10 diagnostic studies comparing SPECT or SPECT/computed tomography (CT) with magnetic resonance imaging, CT, scintigraphy, or clinical examination. Furthermore, we found 8 studies comparing the effect of facet block intervention in SPECT-positive and SPECT-negative patients with cervicogenic headache, neck pain, and lower back pain. Five surgical studies describing the effect of fusion for facet arthropathy in the craniocervical junction, subaxial cervical spine, or the lumbar spine were identified.

CONCLUSIONS

According to the available literature, a positive finding on SPECT in facet arthropathy is associated with a significantly higher facet blockade effect. Surgical treatment of positive findings has a good effect, but this has not been confirmed by controlled studies. SPECT/CT might therefore be a useful method in the evaluation of patients with neck or back pain, especially in cases of unclear findings or multiple degenerative changes.

SPECT-CT as a Predictor of Pain Generators in Patients Undergoing Intra-Articular Injections for Chronic Neck and Back Pain

BACKGROUND

The ability to accurately predict pain generators for chronic neck and back pain remains elusive.

OBJECTIVE

We evaluated whether injections targeted at foci with uptake on single-photon emission computerized tomography-computed tomography (SPECT-CT) were associated with improved outcomes in patients with chronic neck and back pain.

METHODS

A retrospective review was completed on patients undergoing SPECT-CT for chronic neck and back pain between 2016 and 2020 at a tertiary academic center. Patients' records were reviewed for demographic, clinical, imaging, and outcomes data. Only those patients who had facet injections after SPECT-CT were included in this evaluation. Patients undergoing injections targeted at foci of abnormal radiotracer uptake were compared with patients without uptake concerning immediate positive response, visual analog scale, and the need for additional injection or surgery at the target level.

RESULTS

A total of 2849 patients were evaluated with a SPECT-CT for chronic neck and back pain. Of those, 340 (11.9%) patients received facet joint injections after SPECT-CT. A propensity score regression analysis adjusted for age, gender, body mass index, hypertension, multiple target injections, and injection location showed uptake targeted injections not being associated with an improved immediate positive response (odds ratio: 0.64; 95% confidence interval: 0.34-1.21; P = 0.172). In patients with a failed facet injection preceding SPECT-CT, adding SPECT-CT to guide facet injections was associated with a decrease in visual analog scale pain scores 2 weeks after injection (P = 0.018), particularly when changes were made to the facets being targeted (P = 0.010).

CONCLUSION

This study suggests that there is benefit with SPECT-CT specially to guide facet injections after failed prior facet injections.

Imaging of facet joint diseases

Facet joints are the important articular pillars of the spine. Several pathologies can occur in and around the facet joint, including extra ossicles, traumatic dislocation, osteoarthritis, synovial cyst, axial spondyloarthritis, rheumatoid arthritis, calcium pyrophosphate deposition disease, septic arthritis, and malignant and benign neoplasms. Imaging is the mainstay to detect and characterize these diseases. In this review, we discuss the anatomy and function of facet joints, imaging techniques, and the imaging findings of several facet joint diseases. This information may be helpful to radiologists to make the correct diagnosis and optimize the management of patients with facet joint diseases.