Solitary bone tumor imaging reporting and data system (BTI-RADS): initial assessment of a systematic imaging evaluation and comprehensive reporting method.
OBJECTIVES
Identify the most pertinent imaging features for solitary bone tumor characterization using a multimodality approach and propose a systematic evaluation system.


METHODS
Data from a prospective trial, including 230 participants with histologically confirmed bone tumors, typical "do not touch" lesions, and stable chondral lesions, were retrospectively evaluated. Clinical data, CT, and MR imaging features were analyzed by a musculoskeletal radiologist blinded to the diagnosis using a structured report. The benign-malignant distribution of lesions bearing each image feature evaluated was compared to the benign-malignant distribution in the study sample. Benign and malignant indicators were identified. Two additional readers with different expertise levels independently evaluated the study sample.


RESULTS
The sample included 140 men and 90 women (mean age 40.7 ± 18.3 years). The global benign-malignant distribution was 67-33%. Seven imaging features reached the criteria for benign indicators with a mean frequency of benignancy of 94%. Six minor malignant indicators were identified with a mean frequency of malignancy of 60.5%. Finally, three major malignant indicators were identified (Lodwick-Madewell grade III, aggressive periosteal reaction, and suspected metastatic disease) with a mean frequency of malignancy of 82.4%. A bone tumor imaging reporting and data system (BTI-RADS) was proposed. The reproducibility of the BTI-RADS was considered fair (kappa = 0.67) with a mean frequency of malignancy in classes I, II, III, and IV of 0%, 2.2%, 20.1%, and 71%, respectively.


CONCLUSION
BTI-RADS is an evidence-based systematic approach to solitary bone tumor characterization with a fair reproducibility, allowing lesion stratification in classes of increasing malignancy frequency.


TRIAL REGISTRATION
Clinical trial number NCT02895633 .


KEY POINTS
• The most pertinent CT and MRI criteria allowing bone tumor characterization were defined and presented. • Lodwick-Madewell grade III, aggressive periosteal reaction, and suspected metastatic disease should be considered major malignant indicators associated with a frequency of malignancy over 75%. • The proposed evidence-based multimodality reporting system stratifies solitary bone tumors in classes with increasing frequencies of malignancy.
['Ribeiro|Guilherme Jaquet|GJ|http://orcid.org/0000-0002-0704-890X', 'Gillet|Romain|R|', 'Hossu|Gabriela|G|', 'Trinh|Jean-Michel|JM|', 'Euxibie|Eve|E|', 'Sirveaux|François|F|', 'Blum|Alain|A|', 'Teixeira|Pedro Augusto Gondim|PAG|']
D000328:Adult D001859:Bone Neoplasms D005260:Female D006801:Humans D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D011446:Prospective Studies D015203:Reproducibility of Results D012189:Retrospective Studies D014057:Tomography, X-Ray Computed D055815:Young Adult
Bone neoplasms Evidence-based medicine Magnetic resonance imaging Multidetector computed tomography