Cone-Beam CT Imaging for Transbronchial Biopsies in Children Open Access

Solid lung lesions in pediatric patients present unique diagnostic challenges. Primary pulmonary and extrapulmonary neoplasms are rare in childhood and occur less frequently than non-neoplastic conditions, such as infections. In adults, cone-beam computed tomography (CBCT) aids bronchoscopic navigation for peripheral lung lesions, facilitating subsequent biopsies. CBCT, combined with 3D segmentation and real-time fluoroscopy (augmented fluoroscopy), has proven especially beneficial during transbronchial biopsies (TBBx) of lung lesions.^[1] However, beyond isolated case reports, the applicability and feasibility of this approach in children have not been established.^[2]

In this pediatric study, we demonstrate the utilization of CBCT and augmented fluoroscopy to guide bronchoscopy navigation and biopsy, aiding in the determination of lung lesion etiology.

A single-center, cross-sectional study was conducted to examine the outcomes of pediatric patients who underwent CBCT-guided TBBx at our institution between January 2018 and April 2023. Patients were eligible for inclusion if they were aged 21 years or younger. Individuals older than 21 years were excluded from the study. The study was approved by the local institutional review board, and the IRB waived informed consent due to the minimal risk involved. Electronic medical record data were de-identified and retrospectively collected, including sex, age at the time of biopsy, prior diagnoses, lesion size, bronchoscope size, biopsy modality, biopsy location, pathological results, and any changes in treatment based on results.

Additional outcome data collected included final diagnosis and operative complications. Mean and average calculations were performed using Microsoft Excel (version 16.89.1, Microsoft Corporation, Redmond, WA, USA). The procedures were performed using flexible fiberoptic bronchoscopy (Olympus, Tokyo, Japan) via either an endotracheal tube (n = 7) or a laryngeal mask airway (n = 4).

Eleven patients (five female patients) underwent CBCT- and augmented fluoroscopy–guided TBBx during the study period. The mean age was 13.4 years (range: 2–21 years). The average pulmonary nodule size was 2.5 cm (range: 0.5–4.9 cm). The predominant underlying diagnosis among the patients was malignancy (n = 7), including squamous cell carcinoma, lymphoma (Burkitt-like, Hodgkin’s), leukemia, Ewing’s sarcoma, and rhabdoid tumor. The remaining four patients had diverse underlying diagnoses, including chronic cough, cystic fibrosis post-lung transplantation, respiratory papillomatosis, and benign hamartoma of the chest.

CBCT enabled successful navigation to, and acquisition of, adequate tissue for histological evaluation in all patients. A 1.1-mm cryoprobe (Erbe Elektromedizin, Tuebingen, Germany) was used in 3 of 11 patients for lung tissue acquisition (Fig. 1A). In contrast, the remaining cases were performed using Alligator Jaw biopsy forceps (Olympus) (Fig. 1B). Histological analysis of tissue acquired via TBBx resulted in a diagnosis in 8 of 11 (73%) patients. Among these, three patients had malignancies or lung metastases of primary malignancies, two had organizing pneumonia, two had infections (anaerobic infection and histoplasmosis), and one had acute alveolar injury. The three malignancies included malignant rhabdoid tumor, Hodgkin’s lymphoma, and non–small-cell lung carcinoma.

For the three patients in whom a diagnosis was not obtained, two underwent further evaluation via transthoracic biopsies, which identified blastomycosis and fibrosis. One remaining patient died due to heart failure complications unrelated to the bronchoscopy before further evaluation could be performed. The most common complication was bleeding (n = 9, Nashville Grade 1 or 2). No pneumothoraces were observed (Table 1).

We present the first study of CBCT-guided TBBx in children. Our findings highlight the safety and efficacy of this technique. The use of augmented fluoroscopy further enhanced the accuracy and precision of the procedure. Although the diagnostic yield in this study was high, it might be improved by performing an additional cone-beam spin with the biopsy instrument advanced into the nodule to confirm its position within the lesion.^[1] However, this was not routinely done to minimize radiation exposure.

Recent studies have compared endobronchial ultrasound and virtual computed tomography navigational bronchoscopy for lung biopsy in children. Both techniques demonstrated comparable diagnostic yields and safety profiles.^[3] Other minimally invasive approaches, such as electromagnetic and robotic bronchoscopy, have also been reported but are limited by small sample sizes.^[4–6] Technologies like robotic bronchoscopy are costly; however, CBCT is available in many pediatric hospitals, particularly for use by radiologists and interventional radiologists.

Thoracoscopic or open lung biopsies can achieve diagnostic yields as high as 98%. Unfortunately, these methods are associated with a substantially higher risk of complications (15–30%), including pneumothorax and significant hemorrhage.^[7,8] Surgical approaches also typically require hospitalization and increase patient discomfort.

Although our study demonstrates a favorable safety and efficacy profile, it has several limitations. The small sample size and lack of direct comparison with other diagnostic modalities limit the generalizability of our findings. In addition, the biopsy instruments used throughout the enrollment period varied, with the 1.1-mm cryoprobe becoming more common in later stages. Cryobiopsies offer the advantage of obtaining larger specimens and avoiding crushing artifacts, potentially improving diagnostic yield. It is important to note that our study population was derived from a quaternary referral center, which may limit the generalizability of our results to other populations.

This study contributes to the growing evidence favoring minimally invasive strategies for assessing airway and lung lesions in children. Research involving larger study populations and comparisons with other investigative modalities will be necessary to further validate the utility of CBCT-guided TBBx in the pediatric setting. Furthermore, the proceduralist's learning curve must also be addressed; proper training, practical experience, and a solid understanding of CBCT technology are required to ensure accurate interpretation.