The ethics committee of the Rijeka University Clinical Hospital Centre approved the conduct of this retrospective study. Written informed consent from patients was not required since this study was considered a review of clinical practice.

This retrospective study included 56 patients who underwent CT-guided transthoracic pleural biopsy at the Department of Radiology, Rijeka University Clinical Hospital Centre, from January 2015 to July 2021. Out of a total number of patients, 80.4% (45 of 56) were male (age 72.93 ± 8.63 years), and 19.6% (11 of 56) were female (age 67.36 ± 14.39 years). The mean patient age was 71.84 ± 10.11 years (range 43–86).

During the period of 6 years, a total of 158 CT-guided transthoracic biopsies of pleural lesions were performed at our institution. The total number of patients excluded from the study was 102 for the following reasons: pleural lesions with thickness measuring 10 mm or more (n = 58), patients who do not have loculated pleural effusion greater than 20 mm (n = 33), and less than 12 months of follow-up after the procedure (n = 11).

Inclusive criteria for this study were small lesions (lamellar or spindle-shaped plaque) of costal pleura with thickness up to 10 mm, and the presence of loculated, gravity independent, pleural effusion, greater than 20 mm, localised immediately adjacent to the target lesion. Due to pleural effusion, the needle did not penetrate the visceral sheet of the pleura nor did it enter the lung parenchyma, thus avoiding the most common complications such as pneumothorax and needle tract bleeding. An additional inclusive criterion was a non-diagnostic cytological analysis of pleural effusion.

We collected patient data (age and sex) consecutively from the hospital information system (Ibis), while TCNB data (lesion size, needle size, number of tissue sampling) were collected from the picture archiving and communication system (PACS).

The multidisciplinary team (radiologist, pulmonologist, thoracic surgeon, pathologist, and oncologist) indicated this diagnostic procedure for suspected pleural malignancy. The interventional radiologist estimated if the pleural lesion was suitable for the biopsy based on a previously performed diagnostic contrast-enhanced chest CT. On the day of the intervention, every patient was admitted to day rehabilitative and curative care at the Department of Pulmonology.

Criteria for the biopsy procedure included the patient’s ability to cooperate adequately and tolerate the supine position. Also, a valid coagulation test (prothrombin time (PT), international normalised ratio (INR), and partial thromboplastin time (PTT)) was required as well as a signed informed consent.

All interventions included in this study were performed by two interventional thoracic radiologists, one (KM) with 20 years of experience and the other with three years of experience in TCNB.

Patient’s position (pronation, supination, or lateral decubitus) was determined based on the lesion localisation.

The procedure begins with a CT scanogram on which a scanning field was determined that encompasses only that part of the thorax in which the target lesion was located. Due to radiation protection, the narrowest possible field was chosen. All biopsies were performed without contrast agents, under the guidance of CT Siemens Somatom Definition AS (128), with a layer thickness of 2 mm.

The puncture site was labelled with a radiopaque marker, followed by preprocedural cleansing of the biopsy site with an antiseptic agent and a subsequent subcutaneous injection of local anaesthetic (2 mL of 2% lidocaine).

After the skin incision, the pleural biopsy was performed with a single needle technique, 16-gauge semi-automated non-coaxial core biopsy needle (Original TEMNO™ Biopsy Device). The lesion was accessed along the upper margin of the lower rib to avoid damage to the vascular and nerve structures. A biopsy needle was led step-by-step to the pleural lesion; after each step, a CT scan was performed to check the needle position. Each needle manipulation and CT scan were performed only during suspended respiration. The number of punctures depended on the specimen quality, resulting in one or two samples. Since at our institution it is not possible to organise the presence of a cytopathologist during the biopsy, we evaluated the quality of the sample based on the morphology, whether the sample was disintegrated, and whether it dissolved in formalin. Two biopsy passes were performed in 47 (83.9%) of patients, while one pleural puncture was performed in only 9 (16.1%) of patients. The obtained tissue cylinders were sent for pathological analysis. After the procedure, a control non-contrast CT scan was performed to detect possible complications (Figs. 1, 2).

Axial scan of a chest CT obtained during CT-guided transthoracic biopsy (histopathological diagnosis: epithelioid mesothelioma)

1a: radiopaque marker immediately next to a 5 mm thick solid pleural lesion (arrowhead)

1b: biopsy needle (arrow)

Axial scan of a chest CT obtained during CT-guided transthoracic biopsy (histopathological diagnosis: epithelioid mesothelioma)

2a: radiopaque marker immediately next to a 4 mm thick solid pleural lesion (arrowhead)

2b: biopsy needle (arrow)

Histopathological results were evaluated and divided into two diagnostic categories. The first diagnostic category included the diagnosis of a malignant pleural tumour confirmed by lesion regression after undergoing oncological therapy or lesion progression despite received therapy. Patients with the above mentioned findings were included in the group of patients with true-positive (TP) results.

The second diagnostic category included patients with negative histopathological findings or those who have been definitively diagnosed with a benign lesion. All patients included in this category were clinically monitored and controlled using non-invasive radiological methods for 6–12 months. In the observed period, if the lesion size regressed or remained the same, they were included in the group of patients with true-negative (TN) results. Patients with negative histopathological findings, whose clinical course and following CT findings referred to the malignant aetiology of pleural disease, were included in the group of patients with false-negative (FN) results. The definitive diagnosis of patients in the FN category was determined by video-assisted thoracoscopic (VATS) biopsy or open surgical biopsy.

Positive histopathological diagnoses after surgery in the case of an operable pleural tumour, regression of lesion size after undergoing oncological therapy, or progression of findings despite therapy were taken as confirmation of diagnosis.

The diagnostic contribution of this method was determined by tests of overall diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values.