Anatomy and Pathology for Radiographers Flashcards

On a PA chest radiograph, the normal cardiothoracic (CT) ratio should be:

Answer: Less than 50% (maximum cardiac diameter < half the maximum thoracic diameter)

A normal CT ratio is less than 0.5 (50%) — the cardiac width should be less than half the total thoracic diameter on a PA projection. A ratio ≥0.5 indicates cardiomegaly.

Pathological fractures differ from traumatic fractures primarily in that pathological fractures:

Answer: Occur through abnormal (diseased) bone with minimal or no trauma

Pathological fractures occur through bone weakened by disease (tumor, infection, metabolic bone disease, Paget's disease) and may result from minimal or even no trauma.

Interstitial pulmonary edema on a chest radiograph is best characterized by which combination of findings?

Answer: Kerley B lines, peribronchial cuffing, vascular redistribution to upper lobes, and septal thickening

Interstitial pulmonary edema produces Kerley B lines (septal lines), peribronchial cuffing (thickened bronchial walls), upper lobe vascular redistribution, and perihilar haze — all from fluid in the interstitium.

A lytic lesion in the proximal humerus of a 65-year-old patient with a known history of prostate cancer and a long history of bone pain most likely represents:

Answer: Metastatic disease (bone metastasis from prostate cancer)

In a patient over 40 with known primary malignancy, a lytic bone lesion is metastatic disease until proven otherwise — prostate cancer can produce lytic lesions despite typically being blastic.

The radiographic finding of a 'codman triangle' in an aggressive bone lesion indicates:

Answer: Periosteal reaction at the margin of a rapidly growing tumor where the periosteum is elevated but cannot keep up with the tumor

Codman's triangle is a triangular area of periosteal new bone formation at the edge of an aggressive bone lesion (classically osteosarcoma) where rapidly expanding tumor elevates the periosteum faster than new bone can form.

On an AP radiograph of the knee, the normal Insall-Salvati ratio (patellar tendon length to patellar length) is approximately:

Answer: 1.0 (range 0.8–1.2)

The Insall-Salvati ratio = patellar tendon length / patellar length. A normal ratio is approximately 1.0 (±0.2). Ratio >1.2 = patella alta (high patella); ratio <0.8 = patella baja (low patella).