Ultrasonography is very useful for diagnosis of minor or linear fracture of rib.
In minor fracture of rib, doctor can see several phase of findings of rib fracture.
In early phase, doctor can only see  soft tissue swelling(case 1) of minor step of of rib cortex(case 2).
Usually  callus formation  take place 2 weeks after of injury, then   doctor can see bony mass(callus) .
If there is no trauma history  or visualization of callus so ealry , doctor consider the possibility of tumors of rib.
As like this case, visualization of osteoblastic lesion and osteolytic lesion in simultaneously  suggests a malignant mass.
     

referance
1. imagingTumors of the rib

https://www.sciencedirect.com/science/article/pii/S2211568413001952

2. High-resolution sonography of the rib: can fracture and metastasis be differentiated?

https://www.ajronline.org/doi/pdf/10.2214/ajr.184.3.01840969

CT image