We conducted a retrospective investigation involving all patients with a lung lesion who underwent a CT-guided biopsy at our institution between January 2019 and 2021. The mentioned period was investigated due to the introduction in the daily practice of a tru-cut needle for lung biopsy, not used before.

The inclusion criteria were: (a) Procedures performed using either one of the following two needle systems: a fully automated tru-cut (ACECUT 18G-GMG Med Srl) or a semi-automatic full core (BIOMOL 18G-H.S. Spa) for new lung lesions, (b) CT images demonstrating the position of the needles within the lesion, (c) histopathological result of the biopsy and (d) clinical follow-up for at least 12 months and\or surgical histopathological results.

All methods or experimental protocols were approved by the local institutional review board and were carried out in accordance with relevant guidelines and were conducted according to the guidelines of the Declaration of Helsinki. Informed consent was obtained from all participants and/or their legal guardians.

The ACECUT needle is a single-use sterilized fully automated biopsy device equipped with a rapid firing side notch. It uses a two-stage biopsy action. ACECUT makes use of a spring action that rapidly propels the inner trocar frontward, with the outer cutting cannula following suit straightaway in a similar forward thrust. As a result, the tissue sample is promptly caught in the side notch of the trocar during the advancement of the cutting cannula. It possesses a function that can individually fire the inner and outer needles with a penetration depth of 22 mm. (There is another available tip of 11 mm not used in our series.) Moreover, it is possible to use a single-use coaxial guide needle with a trocar point, depending on the operators’ preference, to assist in the introduction of the biopsy needle. The lengths available ranges from 75 to 200 mm.

The BIOMOL needle is a single-use sterilized semi-automated biopsy device that necessitates manually advancing the trocar to uncover the side notch. When pressure is applied to its plunger, the cutting cannula is propelled forward, entrapping the specimen in the containing side notch of the trocar. It automates the procedure while keeping sensitivity during the sampling. The size available varies from 16 to 22 gouge with different lengths available.

The size and lengths of each needles are chosen by the operators depending on their preference, the organ and the characteristics of the target lesion.

All procedures were performed after written informed consent was obtained from the patients.

During the biopsy procedure, preliminary helical CT scan images of the lung were acquired in 1 mm thick slices. From a review of preliminary images, the patient’s position, level of the needle entry site and direction of the approach were planned to provide the most direct route for the biopsy, to go through the shortest track of aerated lung and to avoid bullae and fissures. The procedure was performed by one of four interventional radiologists with more than 5 years of experience on percutaneous CT-guided biopsy or from residents under their direct supervision.

The utilization of the coaxial technique depended on the preference of the operator performing the biopsy. All procedures were performed using a 256 (Brilliance ICT 256, Philips Healthcare, Cleveland, OH, EE, UU) multislice spiral scanner under fluoroscopy guidance.

The radiologist wore a shielding lead apron and was in charge of controlling the CT fluoroscopic exposure using a foot pedal. A sterile field was prepared along the thoracic skin for the proper execution of the procedure. Operators executed the pulmonary biopsy utilizing a real-time CT fluoroscopic method.

The cytopathologist was not present on site during the procedure; hence, biopsy outcome could not be obtained immediately after sampling. Every tissue sampling was conducted under the administration of local anesthesia. Subsequently, thoracic CT scans were acquired to identify potential complications, such as pneumothorax, which may have arisen during the procedure. For patients who exhibited moderate to severe pneumothorax, immediate manual aspiration of air from the pleural space was performed. When the pneumothorax did not reduce, an 8Fr chest drainage tube was placed. Specimens obtained by biopsies were evaluated histologically and cytologically by experienced cytopathologists.

Taking into consideration that the population was rather homogeneous in terms of age and sex, the following parameters were assessed: (1) technical success rate, (2) number of samples obtained in a single biopsy procedure, (3) size of the target lesion according to the longest diameter, (4) distance of the target lesion from the pleura access, (5) basal location and (6) rate and type of complications.

Technical success was defined when there was confirmation on the CT fluoroscopic image that the target lesion was touched or completely penetrated by the biopsy needle.

The biopsy sample was considered as “nondiagnostic” if it was not adequate to obtain a specific benign or malignant disease. Histological findings of percutaneous lung biopsy were compared with the final diagnosis obtained after needle biopsy by independent surgical pathology or clinical\radiological follow-up.

Distance of the target lesion from the pleura access was evaluated considering the optimal needle trajectory avoiding big size vessels, visible bronchi and interlobular fissures.

A lesion was categorized as being situated in a lung’s basal segment if, within one CT slice, both a portion of the diaphragm and the neoplasm were present, a feature that has been noted as a limiting factor of percutaneous lung biopsies [7].

As complications, the incidence of pneumothorax, hemothorax and hemoptysis was evaluated. Regarding pneumothorax, the rates of administration of manual aspiration and tube placement were investigated.

All the dependent variables were compared between the ACECUT group and the BIOMOL group.

Continuous variables were reported as mean (standard deviation, SD) or median (interquartile range, Q1–Q3). Distribution was checked for normality using the Shapiro–Wilk test. Categorical variables were presented as absolute number (n) and relative percentage frequency (%).

Variables were tested for significant differences between the two groups of full-core needle versus tru-cut needles.

To compare continuous variables between two groups, a two-tailed T-test was used when normally distributed, whereas a Mann–Whitney U test was used when not normally distributed. Fisher exact test was performed to test the association between categories for dichotomous variables.

Post hoc power analysis has been conducted with the software G*Power version 3.1.

A multivariable analysis was performed running a binary logistic regression with stepwise forward selection, to further investigate differences in the two population.

A p value of 0.05 was considered statistically significant.

The software BM SPSS Statistics for Windows, Version 24.0 was used for all the statistical analyses.