Technetium-99m Methylene Diphosphonate Single-photon Emission Computed Tomography/Computed Tomography of the Foot and Ankle

Short-Term Outcomes of Intraarticular Corticosteroid Injection into the Lumbar Facet Joint According to the Findings of Single-Photon Emission Computed Tomography Imaging

Objective

Bone single-photon emission computed tomography (SPECT) preferentially localizes areas exhibiting greater bone remodeling and enhanced perfusion, which helps identify areas of pain and inflammation in the lumbar facet joints (LFJs). Herein, we investigated the treatment outcome of intraarticular (IA) corticosteroid injection in patients with LFJ-origin lower back pain (LBP) depending on the presence of increased LFJ uptake on bone SPECT.

Methods

We retrospectively recruited 38 patients with LFJ-origin LBP. Of the 38 patients, 22 patients showed increased uptake on bone SPECT (SPECT+ group), and 16 patients did not show increased uptake on bone SPECT (SPECT- group). A numeric rating scale (NRS) was used to assess pain reduction 1 month after treatment with a corticosteroid injection. Treatment was considered successful when the posttreatment NRS score was ≥50% lower than the pretreatment NRS score.

Results

The NRS scores of the SPECT+ group at the 1-month follow-up were significantly lower than those of the SPECT- group. Additionally, the degree of change in the NRS scores was larger in the SPECT+ group than that in the SPECT- group. In addition, 18 of the 22 patients (81.8%) in the SPECT+ group underwent successful treatment. Eight of the 16 patients (50%) in the SPECT- group underwent successful treatment. The ratio of successful treatment was significantly higher in the SPECT+ group than in the SPECT- group.

Discussion

Bone SPECT could help predict the therapeutic outcome after IA LFJ corticosteroid injection and determine the treatment plan for patients with LFJ-origin LBP.

The Value of SPECT-CT in Diagnosing Complex Non-Arthritic and Non-Neoplastic Conditions of the Foot and Ankle

INTRODUCTION

There is little information on the value of using single photon emission computerized tomography-computed tomography (SPECT-CT) in non-arthritic and non-neoplastic conditions of the foot and ankle (F&A). The vast majority of studies have investigated the role of SPECT-CT in degenerative conditions, bony pathology, and neoplastic conditions. The diagnostic value of SPECT-CT in purely non-arthritic and non-neoplastic conditions, in the absence of other conclusive radiological findings, is yet to be clarified. The aim of this study was to evaluate the value of SPECT-CT in a cohort of patients with complex F&A pathology, in whom diagnostic uncertainty existed after conventional imaging techniques, and to assess its added value in routine clinical practice.

METHODOLOGY

A retrospective analysis of 297 SPECT-CTs from 2010 to 2017 found 18 SPECT-CTs (age = 16-56 years) performed for non-arthritic F&A pathology. Changes in diagnosis, management, and clinical outcome scores were recorded before and after SPECT-CT imaging.

RESULTS

The results demonstrated that the provisional diagnosis was different from the SPECT-CT diagnosis in 10 (56%) out of the 18 patients and led to a modified treatment plan, which was successful in 8 (80%) out of the 10 patients. The post-intervention Manchester Oxford Foot Questionnaire (MOX-FQ) and Visual Analogue Scale (VAS) score improved from 76 ± 18 to 58 ± 24 (P = .02), and from 72 ± 17 to 49 ± 32 (P = .01), respectively. The SPECT-CT scan was useful in confirming the provisional diagnosis in the remaining 8 patients where a diagnostic uncertainty existed after conventional imaging techniques. Overall, a total of 15 out of 18 patients (83%) showed an improvement in their symptoms after management led by SPECT-CT diagnosis.

CONCLUSION

Our study highlights the added value of SPECT-CT in patients presenting with non-arthritic and non-neoplastic F&A conditions in which there is diagnostic uncertainty after conventional imaging. In 80% of cases, a change in management driven by the SPECT-CT findings led to a successful outcome. We have found SPECT-CT to be a useful investigative modality in assessing these complex F&A cases.

LEVELS OF EVIDENCE

Level IV.

Osteochondral Lesions of the Talus: A Review on Talus Osteochondral Injuries, Including Osteochondritis Dissecans

This is a review on talus osteochondritis dissecans and talus osteochondral lesions. A majority of the osteochondral lesions are associated with trauma while the cause of pure osteochondritis dissecans is still much discussed with a possible cause being repetitive microtraumas associated with vascular disturbances causing subchondral bone necrosis and disability. Symptomatic nondisplaced osteochondral lesions can often be treated conservatively in children and adolescents while such treatment is less successful in adults. Surgical treatment is indicated when there is an unstable cartilage fragment. There are a large number of different operative technique options with no number one technique to be recommended. Most techniques have been presented in level II to IV studies with a low number of patients with short follow ups and few randomized comparisons exist. The actual situation in treating osteochondral lesions in the ankle is presented and discussed.

Proposal of a new CT arthrographic classification system of osteochondral lesions of the talus

BACKGROUND

Surgical treatment of osteochondral lesions of the talus (OLT) is warranted if medical treatments fail, achieving good results in around 85% of cases. Numerous classification systems, based on all possible imaging modalities (radiography, MRI, CT scan, scintigraphy, and CT arthrography), have been proposed to guide surgical treatments, but none has proven to be superior. A recent study demonstrated the prognostic value of CT arthrography by accurately describing the subchondral bone plate. A systematic review of the literature has brought new criteria to predict good outcome following bone marrow stimulation surgical techniques: lesions should measure less than 1 centimeter in size and 5 millimeters in depth. Based on these data, we are proposing a new simple, 3-stage CT arthrographic classification system of OLT.

MATERIALS AND METHODS

After a brief overview of the classification, 60 CT-arthrographies of ankles with OLT were organized according to this new CT arthrographic classification system by four surgeons (two juniors and two seniors). Two imaging assessments were performed one month apart. Statistical analysis was performed using the Fleiss' kappa coefficient to determine the inter- and intraobserver agreement.

RESULTS

An excellent inter- and intraobserver agreement was found with overall Fleiss' kappa coefficients of 0.897 and 0.847, respectively.

CONCLUSION

The results of our study showed an excellent inter- and intraobserver agreement for this new CT arthrographic classification system of OLT. The principal advantage of this new classification system, based on the latest data in the literature, is its ability to easily distinguish lesions that are more amenable to bone marrow stimulation techniques.

LEVEL OF EVIDENCE

II.

The added value of SPECT/CT in the painful foot and ankle: A review of the literature

INTRODUCTION

Foot and ankle injuries are common. Radiographic assessment is difficult because of the complex anatomy. In the past decade SPECT/CT made its introduction in assessing bone pathology, it combines both morphologic and pathologic imaging in one image aiming to increase sensitivity and specificity when compared with MRI or CT alone. The purpose of this review was to provide a literature overview on the diagnostic value of SPECT/CT in foot and ankle pathology.

METHODS

A literature search was conducted in the databases of PubMed and EMBASE between January 2004 and September 2019 for articles describing the diagnostic value of SPECT/CT in foot and ankle pathology. For assessment of methodological quality of each study included in the analysis, QUADAS-2 checklist was used. Main outcomes were change of management, improved diagnosis and symptomatic improvement.

RESULTS

A total of eight studies were identified describing the diagnostic value of SPECT/CT in foot and ankle pathology based on patient data. The combined analysis shows that change of management and improved diagnosis occurred in 48-62% and 40-79% of the patients when compared with other imaging modalities and/or clinical assessment. Symptomatic improvement due to treatment based on SPECT/CT findings occurred in 92% of the patients.

CONCLUSION

SPECT/CT is useful when diagnosis based on other imaging modalities is inconclusive or when treatment based on these modalities does not lead to the desired symptomatic improvement.

A retrospective multicenter study of quantitative bone SPECT/CT to predict the surgical removal of the accessory navicular bone

OBJECTIVE

The maximum standardized uptake value (SUVmax) in single-photon emission computed tomography/computed tomography (SPECT/CT) can help quantify disease activity of the accessory navicular bone (ANB). In this multicenter quantitative bone SPECT/CT study, we investigated whether SUVmax was correlated with ANB severity, thereby allowing prediction of surgical resection for ANB treatment.

METHODS

Two-hundred forty-six patients (men:women = 135:111, mean age = 39.3 years), who had undergone quantitative Tc-99m diphosphonate SPECT/CT of the feet, were recruited from four hospitals. SUVmax was measured using vendor-provided quantitation software. The SUVmax values were compared in relation to ANB type (type 1 = 62, type 2 = 136 and type 3 = 14), presence of pain and surgical treatment.

RESULTS

SUVmax (mean ± SD) was the highest in type 2 ANB (4.41 ± 5.2; P = 0.0101). The 17 resected ANBs showed greater SUVmax (8.27 ± 5.23; P < 0.0001) than the 141 asymptomatic ANBs (2.30 ± 1.68) or the 54 symptomatic ANBs without surgery (6.15 ± 4.40). Since surgery is exclusively indicated for ANB type 2, surgical resection was investigated only in these cases. In univariate analysis, young age and SUVmax were significantly associated with surgical treatment, but only SUVmax was a significant predictor of surgery in multivariate analysis (P < 0.0001). Type 2 ANBs were treated by surgery in 32.5% (13/40) of the cases when SUVmax was ≥5, and in only 1.35% (1/74) of the cases when SUVmax was <5 (P < 0.0001).

CONCLUSION

ANB disease activity and excision were strongly associated with the SUVmax derived from quantitative bone SPECT/CT. Our study suggests an absolute SUVmax cutoff for ultimate ANB surgical treatment, but additional prospective studies are required to validate this finding.

Relevance of SPECT-CT in Complex Cases of Foot and Ankle Surgery: A Comparison With MRI

BACKGROUND

Finding the right diagnoses in patients with complex foot and ankle disorders can be challenging. Single-photon emission computed tomography and computed tomography (SPECT-CT) has shown to be feasible in foot and ankle surgery. The aim of this study was to evaluate the reliability and accuracy of SPECT-CT and thereby its impact on final treatment decision compared with magnetic resonance imaging (MRI).

METHODS

A retrospective study was performed on 49 patients treated at our institution. Experienced foot and ankle surgeons independently, and blinded, analyzed clinical data and radiographs together with MRI, SPECT-CT, or a combination of both. Based on the determined final treatment decision Cohen's kappa values were calculated to illustrate interrater and intrarater reliability.

RESULTS

The kappa values for interrater reliability were higher for SPECT-CT at .68 and MRI + SPECT-CT at .71 compared to 0.38 for MRI alone (P < .05). The kappa values for intrarater reliability of MRI + SPECT-CT were higher at .75 compared with SPECT-CT alone at .67 (P < .05) and MRI at .35 (P < .01).

CONCLUSION

We found a higher interrater and intrarater reliability for SPECT-CT compared with MRI alone for diagnosing complex foot and ankle pathologies. SPECT-CT has a high impact on final treatment decision. The main indications are bony pathologies with diagnostic uncertainty especially in closely adjacent structures as the joints of the midfoot, occult coalitio, stress fractures, verification or exclusion of nonfusion, periprosthetic disorders after total ankle replacement and osteochondral lesion in cases of combined pathologies.Levels of Evidence: Level IV: Retrospective study.

Unsuspected Accessory Ossicle in Possible Sinus Tarsi Syndrome: The Value of Bone SPECT/CT

Three-phase bone scan was performed for evaluation of possible sinus tarsi syndrome in a 52-year-old man with chronic left ankle pain. MRI was initially read as unremarkable, and there was little symptomatic improvement after intra-articular anesthetic injection. The primary finding that appreciated only delayed bone SPECT/CT images was focal increased uptake associated with a well-corticated 8-mm bony fragment adjacent to the left calcaneus, thought to represent an accessory ossicle within the left sinus tarsi. The increased uptake suggested fracture or severe degenerative change of the ossicle, likely contributing to the patient's chronic pain.

Nuclear Medicine for the Orthopedic Foot and Ankle Surgeon

Nuclear medicine has been widely applied as a diagnostic tool for orthopedic foot and ankle pathology. Although its indications have diminished with improvements in and the availability of magnetic resonance imaging, nuclear medicine still has a significant and valuable role. The present article offers a comprehensive and current review of the most common nuclear imaging modalities for the orthopedic foot and ankle surgeon. Methods discussed include bone scintigraphy, gallium citrate scintigraphy, labeled-leukocyte scintigraphy, and single-photon emission computed tomography (SPECT). We review the indications and utility of these techniques as they pertain to specific foot and ankle conditions, including osteomyelitis, stress fractures, talar osteochondral lesions, complex regional pain syndrome, oncology, plantar fasciitis, and the painful total ankle arthroplasty. We conclude with a discussion of our approach to nuclear medicine with illustrative cases. Level of Evidence: Level V, expert opinion.

Preliminary Experience With SPECT/CT to Evaluate Periarticular Arthritis Progression and the Relationship With Clinical Outcome Following Ankle Arthrodesis

BACKGROUND

Single photon emission computed tomography combined with computed tomography (SPECT/CT) could potentially aid in diagnosing periarticular arthritis/activity and progression, facilitate effective treatment options, and evaluate the effect surgery has on the clinical outcome of patients with ankle arthritis. The goal of our study was to assess SPECT/CT activity in the ankle and periarticular joints before and after ankle fusion surgery and determine whether it was associated with clinical pain and function scores.

METHODS

Thirty-four patients recruited into this study underwent either arthroscopic or open ankle fusion. X-ray (XR) and SPECT/CT imaging was obtained as well as completion of patient Ankle Osteoarthritis Scale (AOS) and 36-item Short Form Survey (SF-36) questionnaires preoperatively and at 6 months postoperatively. Ankle, subtalar, and talonavicular joint arthritis grading on XR and CT, along with SPECT/CT activity, was evaluated by 2 nuclear medicine radiologists. Data were assessed for normality and analyzed with the appropriate comparative test. P value was set at <.05. Thirty patients (31 ankles) completed follow-up and were analyzed.

RESULTS

SPECT/CT activity showed no significant difference in the ankle joint at 6 months postoperatively while periarticular joint activity significantly increased (P < .05). Six months postoperatively, patients had significant improvements in their AOS and SF-36 scores (P < .05). SPECT/CT grading of all joints analyzed, however, was not associated with AOS or SF-36 scores preoperatively or at 6 months postoperatively.

CONCLUSION

In this study, intensity of activity as evaluated by SPECT/CT in periarticular hindfoot joints in patients who had ankle arthrodesis was not associated with clinical/functional scores at 6 months postoperatively.

LEVEL OF EVIDENCE

Level IV, diagnostic study.

Advanced modalities of molecular imaging in precision medicine for musculoskeletal malignancies

Musculoskeletal malignancies consist of a heterogenous group of mesenchymal tumors, often with high inter- and intratumoral heterogeneity. The early and accurate diagnosis of these malignancies can have a substantial impact on optimal treatment and quality of life for these patients. Several new applications and techniques have emerged in molecular imaging, including advances in multimodality imaging, the development of novel radiotracers, and advances in image analysis with radiomics and artificial intelligence. This review highlights the recent advances in molecular imaging modalities and the role of non-invasive imaging in evaluating tumor biology in the era of precision medicine.

Maximum standardized uptake value of foot SPECT/CT using Tc-99m HDP in patients with accessory navicular bone as a predictor of surgical treatment

Quantitative bone SPECT/CT (single-photon emission computed tomography/computed tomography) using Tc-99m hydroxymethylene diphosphonate is emerging as a useful imaging modality for skeletal diseases. Accessory navicular bone (ANB) has been evaluated by bone scintigraphy only qualitatively and semiquantitatively. However, a truly objective quantitative assessment of ANB is lacking. Here, we measured the maximum standardized uptake value (SUVmax) of the ANB and investigated its usefulness as an imaging biomarker for ANB.Consecutive quantitative bone SPECT/CT studies that had been performed on the foot were retrospectively analyzed. One hundred five patients (male:female = 44:61; median age = 32.0 [range, 11-81] years old; 31 negative controls without ANB and 74 patients with ANB [7 unilateral and 67 bilateral]) and their 210 feet were investigated. The ANBs were classified into types I, II, III (Geist classification), and 0 (contralateral navicular of unilateral ANB). Type II ANBs were subclassified into II-1 (with bony abnormality) or II-0 (without bony abnormality). The treatment modality was observation, conservative treatment, or surgical removal. The associations between the SUVmax and clinical findings, including surgery, were investigated.Patients with type II-1 ANB had the highest SUVmax among all ANB types (P < .001). The SUVmax of symptomatic ANB was greater than that for asymptomatic ANB (P < .001), and the SUVmax for the surgically resected ANB group was also significantly higher than that for the observation only or conservative treatment group (P < .001). Subtype II-1 had a significantly higher SUVmax compared with subtype II-0 (P < .001). Logistic regression analyses in type II ANB showed that young age (P = .020) and SUVmax (P = .031) were significant predictors for surgery. Receiver operating characteristic curve and survival analyses revealed an optimal SUVmax cutoff of 5.27 g/mL for predicting final surgical treatment.SUVmax derived from quantitative bone SPECT/CT was strongly associated with symptom, surgical treatment, and a known high-risk type of ANB. Risk stratification for final surgical treatment of ANB can be achieved using the SUVmax from quantitative bone SPECT/CT.

The role of hybrid bone SPECT/CT imaging in the work-up of the limping patient: a symptom-based and joint-oriented review

A vast spectrum of lower limb bone and joint disorders (hip, knee, ankle, foot) present with a common clinical presentation: limping. Too often this symptom generates an inefficient cascade of imaging studies. This review attempts to optimise the diagnostic effectiveness of bone scintigraphy using the hybrid SPECT/CT technique in relation to the diagnostic clues provided by other imaging modalities, discusses the appropriate clinical indications, optimal scintigraphic procedures and illustrates updated image pattern-oriented reporting. Frequent lower limb bone and joint pathologies that can now be reliably diagnosed using hybrid bone SPECT/CT imaging will be reviewed. Bone SPECT/CT can be an effective problem-solving tool in patients with persistent limping when careful history taking, clinical examination, and first-line imaging modalities fail to identify the underlying cause.

SPECT/CT in Postoperative Foot and Ankle Pain

Postoperative pain is a clinically relevant issue in orthopedic patients, affecting more than 40% 1 year after foot and ankle surgery. Because of the very complex anatomy with many different joints and several motion axes, clinical examination and conventional imaging are sometimes not sufficient to identify a local pain generator. Local uptake of bone-seeking radiopharmaceuticals is known to correlate accurately with sites of pain generating foci and, thus, bone scintigraphy has been an established method to evaluate these respective patients for many years. However, the specificity is rather low if only planar images are acquired. The development of SPECT and especially of hybrid SPECT and CT imaging has significantly enhanced the specificity of this technique. The combination of both functional and morphological imaging, ideally performed with a dedicated SPECT/CT system to minimize misregistration owing to motion artifacts and to enhance image quality by attenuation correction, allows an early and reliable detection of pathologic bone processes, even in patients where radiological imaging with MRI or CT is hampered by metal implants. In diabetic patients with a neuropathic Charcot osteoarthropathy, infection can be differentiated from inflammatory bone alterations (causing bone marrow edema) almost certainly using SPECT/CT with radiolabeled white blood cells and antigranulocyte antibodies, allowing an individual and precise treatment planning either in the initial course of the disease or even after surgery. This article reviews the most frequent clinical challenges in patients after foot and ankle surgery, including a description of the various surgical procedures, the different imaging options with their advantages and disadvantages, and aims to integrate bone SPECT/CT into the clinical diagnostic workup.