Diagnostic performance of tomosynthesis for evaluation of bone tumors and tumor-like lesions: a comparison with radiography

Background Even though radiologic diagnosis of bone tumors and tumor-like lesions is usually based on radiographs, radiographically faint imaging features sometimes remain challenging due to overlapping anatomical structures. Purpose To compare tomosynthesis with radiography for the evaluation of bone tumors and tumor-like lesions. Material and Methods Forty-seven bone tumors and tumor-like lesions were assessed with radiographs and tomosynthesis images. Two radiologists independently analyzed imaging features of lesions, including margin, periosteal reaction, cortical thinning, matrix mineralization, cortical destruction (such as pathologic fracture), and extraosseous soft-tissue extension. Computed tomography (CT) imaging was used as a reference method. Diagnostic performances of radiography and tomosynthesis were analyzed and compared based on sensitivity, specificity, accuracy, positive predictive value, and negative predictive value. Effective radiation dose was compared among the three imaging modalities by phantom studies. Results Inter-observer variability (kappa value) for imaging features was slight to moderate on radiography (0.167–0.588), whereas it was nearly perfect on tomosynthesis (0.898–1.000) except for extraosseous soft-tissue extension (0.647 vs. 0.647). Tomosynthesis showed significantly higher sensitivity than radiography in evaluating the margin for bone tumors or tumor-like lesions (1.00 vs. 0.85; P = 0.016), and significantly higher accuracy than radiography in evaluating the margin and matrix mineralization for those (1.00 vs. 0.85; P = 0.016 and 0.91 vs.0.77; P = 0.023, respectively). In phantom studies, mean effective radiation doses were highest in order of CT, tomography, and radiography. Conclusion Tomosynthesis increases sensitivity and accuracy of the margin as well as accuracy of the matrix mineralization of bone tumors and tumor-like lesions compared to radiography.

POS1283 SPONDILODISCITIS WITHOUT DOCUMENTED GERM: WHAT THERAPEUTIC MANAGEMENT?

Background:Spondylodiscitis (SD) is an infectious inflammation that affects the vertebrae, vertebral discs and adjacent structures. It may have a bacterial or non-bacterial etiology. Although analysis has improved and identification of pathogens is highly pursued, in one third of cases, no organism can be identified.Objectives:The objective of our work is to describe the epidemiological, clinical and evolutionary profile of SD with no germ identified and management.Methods:This is a retrospective study including 37 cases of SD with no germ identified, collected in the Rheumatology Department of Farhat Hached hospital in Sousse, Tunisia over a period of 22 years (1998-2020).Results:The mean age was 59.7 years [18-97 years]. These were 21 men (56.76 %) and 16 women (43.24 %).Spinal pain was the major symptom. The lumbar location was the most frequent in 56.76% of cases. It was a multifocal localization in 21.62%. The imaging allowed the detection of para abscesses -vertebral in 43.24%. An epiduritis was objectified in 54.05%.CT-guided biopsy was performed in 59.46% and it was not conclusive. A bacteriological survey was carried out and came back negative. Spondylodiscitis was presumed to be tubercular and staphylococcal in respectively 62.16 % and 18.92 %. The tuberculosis origin was retained in view of the chronic evolution, the multi-stage damage in the radiological assessment. While staphylococcal SD was retained due to the presence of cutaneous lesion and subacute evolution. Large-spectrum antibiotic therapy was initiated in the other cases.One case was initially considered to be staphylococcal but with epidural and soft tissue extension tuberculosis was then considered to be the cause. The evolution after initiation of adequate antibiotic treatment was interspersed with neurological complications in one case of tuberculosis SD.Conclusion:Our results show a higher frequency of presumed tuberculosis SD considering the endemicity of our country and the improvement under anti tuberculosis treatment.References:[1]Cornett, C. A., and al. Bacterial Spine Infections in Adults. Journal of the American Academy of Orthopaedic Surgeons, 24(1), 11–18.(2016)[2]Lener, S., and al Management of spinal infection: a review of the literature. Acta Neurochirurgica, 160(3), 487–496.(2018)[3]Homagk, L., and al SponDT (Spondylodiscitis Diagnosis and Treatment): spondylodiscitis scoring system. Journal of Orthopaedic Surgery and Research, 14(1).(2019)Disclosure of Interests:None declared

Assessment of central cartilaginous tumor of the appendicular bone: inter-observer and intermodality agreement and comparison of diagnostic performance of CT and MRI

Background Diagnostic performance, inter-observer agreement, and intermodality agreement between computed tomography (CT) and magnetic resonance imaging (MRI) in the depiction of the major distinguishing imaging features of central cartilaginous tumors have not been investigated. Purpose To determine the inter-observer and intermodality agreement of CT and MRI in the evaluation of central cartilaginous tumors of the appendicular bones, and to compare their diagnostic performance. Material and Methods Two independent radiologists retrospectively reviewed preoperative CT and MRI. Inter-observer and intermodality agreement between CT and MRI in the assessment of distinguishing imaging features, including lesion size, deep endosteal scalloping, cortical expansion, cortical disruption, pathologic fracture, soft tissue extension, and peritumoral edema, were evaluated. The agreement with histopathology and the accuracy of the radiologic diagnoses made with CT and MRI were also analyzed. Results A total of 72 patients were included. CT and MRI showed high inter-observer and intermodality agreements with regard to size, deep endosteal scalloping, cortical expansion, cortical disruption, and soft tissue extension (ICC = 0.96–0.99, k = 0.60–0.90). However, for the evaluation of pathologic fracture, MRI showed only moderate inter-observer agreement (k = 0.47). Peritumoral edema showed only fair intermodality agreement (k = 0.28–0.33) and moderate inter-observer agreement (k = 0.46) on CT. Both CT and MRI showed excellent diagnostic performance, with high agreement with the histopathology (k = 0.89 and 0.87, respectively) and high accuracy (91.7% for both CT and MRI). Conclusion CT and MRI showed high inter-observer and intermodality agreement in the assessment of several distinguishing imaging features of central cartilaginous tumors of the appendicular bones and demonstrated comparable diagnostic performance.

Dural Plasmacytoma Involving Calvarium with Soft Tissue Extension Mimicking Meningioma: A Diagnostic Dilemma

Here, the authors describe a case of 25-year-old man diagnosed with dural plasmacytoma involving calvarium with soft tissue extension. Magnetic resonance imaging (MRI) revealed extra-axial heterogeneously enhancing soft tissue mass lesion in the left parieto-occipital region with a dural tail mimicking meningioma, destroying the left parietal bone, and bulging into the scalp. Mass was excised and histopathologic examination revealed plasmacytoma with amyloid deposition. There is no recurrence after postoperative radiotherapy and 2 years of follow-up, although the future course is still not certain. The clinician should consider alternative diagnosis other than meningioma prior to proceeding to surgery if the dural-based lesion is involving calvarium and soft tissue extension.

Prognostic Significance Of Soft Tissue Involvement and International Prognostic Index In Primary Bone Lymphoma– A Single Institutional Experience

Introduction Primary bone lymphoma (PBL) is a rare disease, representing approximately 7% of malignant bone tumors and 5% of extranodal lymphomas. There is inconsistent data in the literature regarding to definition, stage and prognostic factors. This study aims to describe our institutional experience in comparison with literature to identify any additional potential prognostic indicators. Materials and methods Following the guidelines of Institutional Review Board, we retrospectively reviewed PBLs at Moffitt Cancer Center from 1998 to 2013 using data from medical record, Cancer Registry, and the Social Security Death Index. The pathological diagnosis was confirmed by experienced study pathologists using WHO classification. Clinical and radiological information was confirmed by study oncologists. Results 70 PBLs were included into our study, and most (n=53, 75.7%) were histologically classified as primary bone diffuse large-cell lymphoma (PB-DLBCL) (Table 1. There was a slight male predominance (1.3:1) with a median age of 56.5 years (15-89). Femur, spine and pelvis were most commonly involved. Most patients present with local bone pain (88.5%). Soft tissue extension is common (55.8%). Multifocal bone lesions and Ann Arbor Stage IV disease were observed in 27 patients (38.6%) and 41 patients (44.3%), respectively. Of 70 PBLs, 38.6% were treated with combined modality therapy, 8.6% were treated with radiation therapy alone, and 48.6% were treated with chemotherapy alone. The data of PB-DLBCL subgroup were further analyzed for survival. The patients with PB-DLBCL had 3- and 5-year progression free survival (PFS) of 61.2% and 46.9% respectively, while 5- and 10-year overall survival (OS) were 81.1% and 74.7% (Figure 1). In univariate analysis, soft tissue extension (p=0.009), multifocal lesions (p=0.002), stage IV (p=0.001), elevated LDH (p=0.027), high International Prognostic Index (IPI) score (p<0.001), and single-modality therapy (p=0.004) were significant poor prognostic factors for PFS. Age ≥60 years (p= 0.012), soft tissue extension (p=0.015), multifocal lesions (p<0.001), stage IV (p=0.001), elevated LDH (p= 0.034), high Performance Score (p=0.036), high IPI score (p<0.001), and single-modality therapy (p=0.021) were significant poor prognostic factors for OS. Multivariate analysis revealed that soft tissue extension and IPI score were two independent prognostic factors for both PFS and OS in patients with PB-DLBCL (Table 2). Conclusion Our institutional experience confirms, although PB-DLBCL comprises the majority of PBL, the overall prognosis of PBL is good. In PB-DLBCL, soft tissue extension and higher IPI score are associated with an inferior OS and PFS. The authors emphasized that prognostic significance of soft tissue extension and IPI in PBL are not well discussed in the literature, which warrants further investigation in larger well-characterized clinical cohorts. Disclosures: No relevant conflicts of interest to declare.