Lung conundrum: A case study

Abstract

Background/Aims: A 15 year old male presented to the Lady Cilento Children's Hospital with known Ebstein's anomaly, complicated surgical history, acute pleuritic chest pain and elevated D-dimer. This poster aims to highlight a rare congenital condition and the modified Ventilation/Perfusion (V/Q) lung scan performed to exclude pulmonary embolism after an inconclusive Computed Tomography Pulmonary Angiogram (CTPA) and Computed Tomography Coronary Angiogram (CTCA) due to atypical cardiovascular anatomy. Methods: A protocol was determined using knowledge of the patient's anatomy; the patient's weight was obtained and procedure explained. Ventilation was performed using 99mTc-Diethylenetriaminepentaacic Acid (DTPA) via cadema and Single Positron Emission Computed Tomography (SPECT) and statics were acquired. A half dose 99mTc-Macro Aggregated Albumin (MAA) injection was given via left arm cannula and the first perfusion SPECT and statics were acquired. A second half dose 99mTc-MAA injection was given via left foot cannula and the perfusion SPECT and statics were repeated. Quantitative analysis was performed to determine differential blood flow. Ethics approval and patient consent were obtained to publish a case study poster. Results: Ventilation images showed a defect aligning with known right lower lobe atelectasis, bilateral pleural effusions and an enlarged cardiac silhouette. Images following injection into the left arm showed no left lung perfusion. Images flowing injection into the left foot showed perfusion to the left lung, with minimal increase in the right lung. There were no segmental perfusion defects in either lung. Quantitative analysis demonstrated preferential perfusion of the right lung from blood returning via the superior vena cava, and relatively symmetric perfusion to both lungs from blood returning via the inferior vena cava. Conclusion: Performing modified V/Q scans to exclude pulmonary embolism in patients with atypical cardiovascular anatomy could significantly reduce duplication of inconclusive exams, anxiety, cost to patients and the healthcare system and radiation exposure while maintaining image quality.L6220196892018-05-11 <br />