Diagnostic Imaging
Diagnostic imaging tests modality choice and image interpretation in thoracic and cardiovascular disease. The exam expects you to match the clinical question to the imaging test and to recognize urgent findings.
Core rules
- Chest radiograph is first-line for acute dyspnea, line position and postoperative complications; it is insensitive for early dissection and small emboli.
- CT angiography is first-line for aortic dissection, pulmonary embolism and major vascular injury when the patient is stable enough.
- Echocardiography assesses valve disease, pericardial effusion, ventricular function and tamponade; transesophageal echo is useful intraoperatively and for aortic pathology.
- PET-CT assesses metabolic activity and staging but does not replace tissue diagnosis when infection or inflammation is possible.
Worked example
A stable patient with tearing chest pain and a widened mediastinum on chest radiograph needs CT angiography, not repeat plain films. The reasoning is pretest probability plus urgency: CTA defines intimal flap, extent and malperfusion. If unstable, bedside echo may guide immediate surgery while resuscitation continues.
Traps
Do not exclude dissection with a normal chest radiograph; do not use contrast CT without considering renal function and urgency; do not call PET uptake diagnostic of cancer; do not ignore echocardiographic findings of tamponade because blood pressure is normal.