The Role of a Virtual Noncalcium Dual-Energy CT Application in the Detection of Bone Marrow Edema in Peripheral Osteomyelitis

Purpose: To determine the sensitivity and specificity of dual-energy CT (DECT) virtual noncalcium images (VNCa) with bone and soft tissue reconstructions in the diagnosis of osteomyelitis. Materials & Methods: Between December 1, 2014 to December 1, 2020, 91 patients who had 99 DECT performed for a clinical indication of osteomyelitis with corresponding MRI, triphasic bone scan and/or white blood cell scintigraphy with CT/SPECT performed either 2 weeks before or 1 month after the DECT were retrospectively identified. The presence or absence of osteomyelitis was established using a second imaging test, bone biopsy or surgery. Two radiologists interpreted VNCa images alone and with bone and soft tissue reconstructions for osteomyelitis. Fleiss k statistics was used to assess inter-level agreement. Results: Osteomyelitis was present in 26 cases (26.2%), of which 4 cases (4%) had co-existing septic arthritis. DECT was performed at the following sites: ankle/foot (n = 59), calf (n = 12), knee (n = 3), thigh (n = 7), hip (n = 9), pelvis (n = 6), wrist/hand (n = 1), and shoulder (n = 2). Sensitivity with VNCa images alone was 53.8% and 73.1% and specificity was 84.9% and 71.2%. Sensitivity with VNCa images and bone and soft tissue reconstructions was 80.8% and 80.8% and specificity was 80.8% and 72.6%. Interobserver agreement was 76.7% (76 of 99 cases), for VNCa images alone (k = .487), and 66.7% (66 of 99 patients) for bone and soft tissue reconstructions with VNCa images together (k = .390). Conclusion: When VNCa images were combined with bone and soft tissue reconstructions, there is improved sensitivity in the diagnosis of osteomyelitis.

Diagnostic Accuracy of Dual-energy CT for Bone Marrow Edema in Patients with Acute Knee Injuries: A Systematic Review and Meta-analysis

Background: The prevalence of knee injury is high and early diagnosis is significant to guide clinical treatment. MRI is recognized as the gold standard for detecting bone marrow edema (BME) in patients with acute knee injury, but limitations still exist. Dual-energy CT (DECT) is investigated as a promising alternative.Methods: We systematically retrieved studies from EMBASE, Scopus, PUBMED, and the Cochrane Library and collected gray literatures. According to PRISMA-DTA guidelines, a systematic review was performed from inception to July 31, 2021, assessing the diagnostic accuracy of DECT for detecting BME in at least 10 adult patients with acute knee injuries and with an MRI reference standard. Study details were independently extracted by two reviewers. Meta-analysis was performed using a bivariate mixed-effects regression model with subgroup analysis performed to evaluate for sources of variability. Results: Nine studies evaluating 290 patients between the ages of 23–53 with acute knee injuries undergoing DECT and MRI were included in analysis. Summary sensitivity, specificity, and AUC values for BME were 85% (95% confidence interval (CI) 77–90%), 96% (95% CI 93–97%), and 0.97 (95% CI 0.95–0.98), respectively. There were no statistically significant differences in specificity and sensitivity amongst comparative subgroups to account for presumed variability amongst studies.Conclusion: DECT is accurate for detecting BME in patients with acute knee injuries and can be used as an alternative to MRI, particularly when MRI is contraindicated or unavailable.

Subchondral insufficiency fracture of the knee: review of current concepts and radiological differential diagnoses

Subchondral insufficiency fracture of the knee (SIFK) is a common cause of knee joint pain in older adults. SIFK is a type of stress fracture that occurs when repetitive and excessive stress is applied to the subchondral bone. If the fracture does not heal, the lesion develops into osteonecrosis and results in osteochondral collapse, requiring surgical management. Because of these clinical features, SIFK was initially termed “spontaneous osteonecrosis of the knee (SONK)” in the pre-MRI era. SONK is now categorized as an advanced SIFK lesion in the spectrum of this disease, and some authors believe the term “SONK” is a misnomer. MRI plays a significant role in the early diagnosis of SIFK. A subchondral T2 hypointense line of the affected condyle with extended bone marrow edema-like signal intensity are characteristic findings on MRI. The large lesion size and the presence of osteochondral collapse on imaging are associated with an increased risk of osteoarthritis. However, bone marrow edema-like signal intensity and osteochondral collapse alone are not specific to SIFK, and other osteochondral lesions, including avascular necrosis, osteochondral dissecans, and osteoarthritis should be considered. Chondral lesions and meniscal abnormalities, including posterior root tears, are also found in many patients with SIFK, and they are considered to be related to the development of SIFK. We review the clinical and imaging findings, including the anatomy and terminology history of SIFK, as well as its differential diagnoses. Radiologists should be familiar with these imaging features and clinical presentations for appropriate management.

Role of magnetic resonance imaging on fingers in diagnosis of post-traumatic tendon and ligament injuries

Background Magnetic resonance (MR) imaging is a powerful method for evaluating acute and chronic lesions of the stabilizing articular elements (volar plate and collateral ligaments) of the fingers and thumbs, the condition of tendons, the presence of a tear, the number of affected tendons, the extent of tendon retraction, and the presence of associated lesions. This study was done to clarify the value of magnetic resonance imaging (MRI) in assessment of trauma-related injuries of the tendons and ligaments of the fingers and subsequently positively affect the surgical decisions in such cases. Results This study included 42 patients (33 males and 9 females) with a mean age of 35 years. All of them had history of trauma. Male affection was 78.5%, while females constituted only 21.5%, striking right-sided-hand affection (92.9%). The most affected finger was the thumb. The most common affected sites were extending from the metacarpophalangeal (MCP) till the proximal interphalangeal (PIP). The tendons were affected in 42.9%; meanwhile, ligamentous affection represented 57.2%. The flexor tendon tear represented by 28.6%%, while extensor tendon tear occurred in 14.3%. The study also showed that partial thickness tear is represented by 66.7%, while complete thickness tear occurred in about 33.3%. Bone marrow edema and post-traumatic tenosynovitis occurred in about 14% of cases. Conclusions Magnetic resonance imaging is an essential technique to obtain a correct pre-surgical diagnosis. It is of utmost importance to possess an in-depth knowledge of finger radiological anatomy in detail, as well as the appearance of the different pathologic entities on MRI. It provides a great assessment of the tendons and ligaments tear by whether partial or complete, any associated marrow edema or bony fragment avulsion and the extent of retraction in cases of complete tear.

The evaluation of bone marrow edema in sacroiliac joint in patients with ankylosing spondylitis using magnetic resonance imaging Dixon sequence

Background Bone marrow edema of the sacroiliac joint is the early imaging manifestation, an indicator of inflammatory activity of ankylosing spondylitis (AS) (Yang R, et. al. Medicine (Baltimore) 98:e14620, 2019). Objective The aim of the study was to investigate the value of magnetic resonance imaging (MRI) Dixon sequence in the diagnosis of marrow edema of the sacroiliac joint in patients with AS. Methods Forty-five patients with AS admitted in our hospital between November 2016 and February 2019 were selected retrospectively as the case group. Forty-five healthy subjects recruited between November 2016 and February 2019 served as the control group. Bath ankylosing spondylitis disease activity index (BASDAI), Bath ankylosing spondylitis functional index (BASFI), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were recorded after admission to the hospital. The Dixon sequence water-fat ratio of the iliac and sacral surfaces of the bilateral sacroiliac joints in the study group were compared with indicators above in order to find the correlation. Results The water-fat ratio under the bilateral sacroiliac joints on Dixon sequence images in the case group was significantly higher than that in the healthy control group (P<0.05). The Dixon sequence water-fat ratio of the iliac and sacral surfaces of the bilateral sacroiliac joints in the study group were positively correlated with spinal arthritis research (SPARCC), BASFI and BASDAI score (all P < 0.05), but did not correlate with ESR and CRP. Conclusion The water-fat ratio of magnetic resonance Dixon sequence can be used as a reference index to evaluate the degree of bone marrow edema in active stage of sacroiliac arthritis.

Reviewing Bone Marrow Edema in Athletes: A Difficult Diagnostic and Clinical Approach

Bone marrow edema (BME) is defined as an area of low signal intensity on T1-weighted (T1W) MRI images and associated with intermediate or high signal intensity findings on T2-weighted (T2W) MRI images. BME represents a typical imaging finding that characterizes common stress-related bone injuries of professional and amateur athletes. The etiology of stress-related injuries is influenced by numerous factors, including the initiation of a new sports activity or changes in an existing training protocol. The clinical significance of BME remains unclear. However, a correlation between the imaging pattern of BME, the clinical history of the patient and the type of sports activity practiced is essential for correct diagnosis and adequate therapeutic treatment. It is also important to clarify whether there is a specific threshold beyond which exercise can adversely affect the bone remodeling process, as the clinical picture may degenerate into the presence of BME, pain and, in the most severe cases, bone loss. In our review, we summarize the current knowledge on the etiopathogenesis and treatment options for BME and highlight the main aspects that make it difficult to formulate a correct diagnosis and establish an adequate therapeutic treatment.

Initial Experience with Subchondral Stabilization for Bone Marrow Lesions of the Midfoot and Forefoot

Disabling foot pain is often accompanied by MRI evidence of bone marrow edema which may represent early structural fatigue. Emerging evidence suggests subchondral stabilization with injectable calcium phosphate can alleviate pain associated with bone marrow edema in the hindfoot, ankle and knee; however, there is no data supporting its use or safety for midfoot or forefoot lesions. We identified 54 patients who underwent SS of various midfoot/forefoot osseous structures in our practice over a four-year period. All patients proved recalcitrant to standard conservative measures, and all had advanced imaging appreciating BME. VAS for pain at 1, 3, 6, and 12 months postoperatively served as the primary outcome measure. 41 patients were included with a mean age of 54.3 ± 14.9 years and mean follow up of 14.1 ± 6.9 months. Patients saw a significant decrease in VAS pain as early as 1 month postoperatively (p<0.05). Mean postoperative VAS at 12 months was 2.11 ± 2.50, and the mean reduction in VAS pain from preop to 12 months postop was -5.00 (95% CI -3.44 to -6.56, p<0.05). Fourteen patients (34%, 14/41) were pain free at 12 months. Treatment of more than one bone (unadjusted OR 6.23 [95% CI 1.39 to 27.8], P=0.017) was associated with a greater likelihood of not achieving a pain free status at 12 months. Initial experience suggests that SS was both safe and effective in our patient population. Simultaneous treatment of multiple bones should be entered into with caution, and further research on the subject is necessary. Level of Evidence: IV (Retrospective Case Series)