Evaluation of precision of guidance techniques in image guided fine needle aspiration cytology of thoracic mass lesions

BACKGROUND: Transthoracic fine needle aspiration cytology (FNAC) is an established and safe technique for diagnosis of thoracic mass lesions. Computed tomography (CT) scan depicts clear anatomical details and provides access to any area of the body. It is, however, expensive and the needle is not passed in real time. Ultrasound is cheaper, radiation free, and allows real time monitoring. Its limitations are obscurement of lesions by aerated lung, smaller, deep seated, and cavitary lesions. AIMS: This study aims to compare sensitivity and specificity of CT scan and ultrasonography (USG) in thoracic FNAC. MATERIALS AND METHODS: The study was conducted on patients who presented with thoracic mass lesions in lungs, mediastinum, hilar lymph nodes, thoracic vertebrae, paraspinal soft tissue, and pleura. One hundred and twenty patients were studied. Only those cases in which sonographic guidance was not possible were taken up for CT guided FNAC. The lesions were assigned to benign and malignant categories and into specific diagnoses where possible. Biopsy correlation was available in 113 cases. Patients were lost to follow-up in five lung and two mediastinal masses. STATISTICAL ANALYSIS: Statistical tests applied included diagnostic tests for sensitivity and specificity. RESULTS: An accuracy of 70.8% was found for image guided FNACs with a sensitivity and specificity of 92.2% and 100%, respectively. CT had a sensitivity of 93.2% and specificity of 100%. For USG guidance, the same was 91.3% and 100%, respectively. CONCLUSIONS: Precision of USG and CT scan is comparable for guidance in FNAC from thoracic mass lesions.