This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Radiology
Comment on the diagnosis of CT chest shown below. 
Select and explain. 
A. Aoic dissection, B. Pulmonary embolism, C. Cardiac myxoma, D. Aoic aneurysm
A: Aoic dissection
Answer: A: Aoic dissection 
Explanation: Normal Anatomy in CT Chest: Aoic dissection: M/C site of aoic dissection is Ascending aoa Intimal flap with double lumen is seen IOC for acute aoic dissection CT angiogram (stable pt.) TEE (unstable pt.) In Chronic aoic dissection: IOC: MRI Signs of FALSE LUMEN: Cob Web Sign: Irregularities of False lumen Beak Sign: False lumen forms acute angle with True lumen: SADDLE EMBOLUS: PULMONARY EMBOLISM - Filling Defect seen in Pulmonary aery - IOC for PE: CT Angiography Left atrial Myxoma: - Low annotating hypodense lesion on the posterior most chamber of the hea (Left Atrium) - MC primary Benign cardiac tumor in adults - MC in females - Has dystrophic calcifications Thrombosis within walls of aoic aneurysm : Aoic aneurysm: - Involve either ascending aoa, thoracic aoa & abdominal aoa - Syphilitic aoitis commonly involve ascending aoa causing aoic aneurysm - M/C cause for abdominal & thoracic aoic aneurysm - Atherosclerosis Ascending aoic aneurysmAbdominal aoic aneurysm (axial & coronal view)