Role of Multi-Detector Computed Tomography (MDCT) in Diagnosis of Pulmonary Artery Dissection: A Rare but Fatal Entity.

Dear Editor, A 33-year-old male who was undergoing treatment with phosphodiesterase 5 inhibitor and anticoagulant for idiopathic pulmonary arterial hypertension presented to the emergency department with acute onset of dyspnoea and chest pain. His cardiovascular examination had shown features of cardiomegaly and pulmonary arterial hypertension with no pathological murmur. His blood pressure was 138/100 mm Hg with heart rate 86 per minute. Electrocardiography showed changes suggestive of right ventricular hypertrophy with no evidence of ST segment changes. His troponin T markers for infarction were within normal limits. Chest X-ray (not shown) demonstrated cardiomegaly with biventricular enlargement. There was dilated pulmonary trunk with evidence of peripheral pruning. Patient was referred for urgent multi-detector computed tomography (MDCT) pulmonary angiography to rule out pulmonary thromboembolism. Computed tomography (CT) pulmonary angiography was performed using 64 slice machine (GE,VCT XTE); 120 mL of contrast was administered at the rate of 4.5 mL/sec followed by 40 mL of saline at the same rate. Scanning was performed with bolus track technique with region of interest (ROI) in the right ventricle. Sections of thickness 0.625 mm were acquired. Volume rendered and contrast images were then interpreted. CT scan showed that the main and left pulmonary arteries were grossly dilated. There was evidence of intimal fl ap which originated just cranial to the pulmonary valve (Fig.1) and extended superiorly up to the bifurcation (Fig. 2). True and false lumens could be differentiated due to lesser enhancement and slow fl ow as compared to the true lumen (Fig. 3). Volume rendered (VR) images had shown grossly dilated main and left pulmonary arteries (Fig. 4). No evidence of any pulmonary thromboembolism was