A Prospective, Randomized, Multicentric and Single-blinded Study on Accuracy and Safety of Ultrasound (US) Guided Percutaneous Needle Biopsy of Peripheral Lung Lesion Compared With Computed TomogrAphy (CT) Guided Needle Biopsy

Peripherical pulmonary lesions without endobronchial lesions (LPP) are nowadays more and more frequently found in clinical practice, and it's only assumable that this tendency will keep growing in the future, alongside the increasing use of thoracic CT scanning and the proven efficacy in lung cancer screening. Even though most of these lesions are benign, it's still important to be able to identify neoplastic lesions in an early stage.

The gold standard for diagnosis definition is biopsy, which can be performed by four paths: surgery, transbronchial endoscopy (TBB), endobronchial endoscopy (EBB) or percutaneous (TTNA).

Surgical option is the most reliable one in terms of diagnostic yield, at the expense of an increased risk of complications, post-operative recovery in hospital staying and costs, compared with the other three procedures; due to the safety and diagnostic yield of TBB, EBB and TTNA, the surgical approach, just for the purpose of diagnosis, resulted in a secondary choice in the diagnostic flowchart of LPP. In addiction, given the high probability of the benign nature of the LPP, the choice of a less invasive approach in the diagnostic phase is even more reasonable. Even though technology really improved the diagnostic yield of LPP, overall sensibility is around 70-80%, influenced by many factors such as: localization and extension of the lesion, presence of bronchus sign, sampling techniques and procedural errors. The incidence of complications for this type of sampling, mostly presented by pneumothorax, is around 4%.

The TTNA is a largely used procedure for diagnosing LPP and it can be conducted using both a CT guided and an ultrasound guided approach, as long as the lesion is located in direct contact with the thoracic wall. CT scan guide has the perk of giving a more precise view of: densitometric feature of the lesions, their location and the connections with the anatomical structures surrounding them. LPP CT guided TTNA (tTTNA) can reach a diagnostic yield of 98% in case of an experienced operator, where ultrasound guided reaches about 93.4%, only slightly inferior to the prior one. Both tTTNA and ultrasound guided percutaneous transthoracic biopsy (eTTNA) are useful techniques not only for pulmonary parenchymal diseases but also in case of pleural lesions, allowing simultaneous sampling and visualization of the lesions in exam.

Peripheric pleural lesions can also be approached via thoracoscopy (both medical and surgical) with a diagnostic efficiency between 91-95% for malignant lesions and 100% for Tuberculosis-related lesions. However, the high risk of complications after the procedure, the duration of hospitalization post-surgery and the costs, suggest choosing between eTTNA and tTTNA as the very first diagnostic step in pleural lesions as well. Moreover, the diagnostic yield of tTTNA and eTTNA is respectively of 89% and 90%.