To Biopsy or Not to Biopsy: Imaging Features of Chronic Nonbacterial Osteomyelitis of the Clavicle
Bibliographic record
Abstract
Objectives Chronic nonbacterial osteomyelitis (CNO) of the clavicle can pose a diagnostic challenge as the differential includes malignancy and infection.[1-3] Biopsy is often required for unifocal clavicular lesions as CNO is a diagnosis of exclusion. With recent advances in imaging techniques, we aim to describe features on plain radiograph and MRI that may distinguish CNO from other conditions that must be excluded. Methods This is a single-center retrospective chart review of all patients presenting with a unifocal clavicular lesion who underwent a clavicular biopsy and radiographic imaging between the years of 2000-2022. A diagnosis of CNO or non-CNO was extracted from chart review based on histology and the opinion of the treating physician. Imaging (plain radiograph, MRI) was reviewed by 2 musculoskeletal radiologists blinded to the final diagnosis. Clinical and imaging features were compared between patients diagnosed with CNO and non-CNO diagnoses using Fishers’ Exact Test. Results 41 patients were included in the analysis: 25 patients with CNO and 16 with non-CNO (diagnoses included: aneurysmal bone cyst (n=5), Langerhans Cell Histiocytosis (n=4), leukemia (n=1), infectious osteomyelitis (n=1), Gorham Stout (n=2), fracture (n=1), fibrous dysplasia (n=1) and 1 diagnosis was unknown). All patients had radiography of the clavicles, and 32 patients had MRI. Patients with CNO were more likely to have multifocal lesions on imaging (p=0.01) and were less likely to have fever or weight loss at presentation (p=0.05). CNO lesions on plain film were more likely to be located on the medial clavicle (p=2e-04) with periosteal reaction (p=0.03). On MRI, rhomboid fossa involvement was found in 19 of 25 patients with CNO, and 0 of 16 in those with non-CNO (p=4.87e-07) (Figure). Conclusion This study describes a novel association of rhomboid fossa involvement on MRI with CNO that is not present in non-CNO cases. Multifocal lesions on imaging, absence of fever/weight loss, periosteal reaction on plain film and medial clavicular involvement are supportive features of CNO. MRI is an important diagnostic tool, and it may be possible to avoid biopsy by using imaging modalities in conjunction with clinical features to make the diagnosis of CNO. [1.] Zhao Y. Pediatr Clin North Am 2018;65(4):783-800. [2.] Nico MAC. Insights Imaging 2022;13(1):149. [3.] Andronikou S. Clin Radiol 2019;74(9):737.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".