Radiation exposure in navigated techniques for AIS: is there a difference between pre-operative CT and intraoperative CT?

PURPOSE

Utilization of navigation improves pedicle screw accuracy in adolescent idiopathic scoliosis (AIS). Our center switched from intraoperative CT (ICT) to an optical navigation system that utilizes pre-operative CT (PCT). We aim to evaluate the radiation dose and operative time for low-dose ICT compared to standard and low-dose PCT used for optical navigation in AIS patients undergoing posterior spinal fusion.

METHODS

A single-center matched-control cohort study of 38 patients was conducted. Nineteen patients underwent ICT navigation (O-arm) and were matched by sex, age, and weight to 19 patients who underwent PCT for use with an optical-guided navigation (7D, Seaspine). A total of 418 levels were instrumented and reviewed. PCT was either a standard dose (N = 7) or a low dose (N = 12). The mean volume CT dose index, dose-length product, overall effective dose (ED), ED per level instrumented, and operative time per level were compared.

RESULTS

ED per level instrumented was 0.061 ± 0.029 mSv in low-dose PCT and 0.14 ± 0.05 mSv in low-dose ICT (p < 0.0001). ED per level instrumented was significantly higher in standard PCT (1.46 ± 0.39 vs. 0.14 ± 0.03 mSv; p < 0.0001). Mean operative time per level was 31 ± 7 min for ICT and 33 ± 3 min for PCT (p = 0.628).

CONCLUSION

Low-dose PCT resulted in 0.70 mSv exposure per case and 31 min per level, standard-dose was 16.95 mSv, while ICT resulted in 1.34-1.62 mSv and a similar operative time. Use of a standard-dose PCT involves radiation exposure about 9 times higher than ICT and 23 times higher than low-dose PCT per level instrumented.

LEVEL OF EVIDENCE

Level III.

Preoperative CT-based radiomics combined with tumour spread through air spaces can accurately predict early recurrence of stage I lung adenocarcinoma: a multicentre retrospective cohort study

OBJECTIVE

To develop and validate a prediction model for early recurrence of stage I lung adenocarcinoma (LUAD) that combines radiomics features based on preoperative CT with tumour spread through air spaces (STAS).

MATERIALS AND METHODS

The most recent preoperative thin-section chest CT scans and postoperative pathological haematoxylin and eosin-stained sections were retrospectively collected from patients with a postoperative pathological diagnosis of stage I LUAD. Regions of interest were manually segmented, and radiomics features were extracted from the tumour and peritumoral regions extended by 3 voxel units, 6 voxel units, and 12 voxel units, and 2D and 3D deep learning image features were extracted by convolutional neural networks. Then, the RAdiomics Integrated with STAS model (RAISm) was constructed. The performance of RAISm was then evaluated in a development cohort and validation cohort.

RESULTS

A total of 226 patients from two medical centres from January 2015 to December 2018 were retrospectively included as the development cohort for the model and were randomly split into a training set (72.6%, n = 164) and a test set (27.4%, n = 62). From June 2019 to December 2019, 51 patients were included in the validation cohort. RAISm had excellent discrimination in predicting the early recurrence of stage I LUAD in the training cohort (AUC = 0.847, 95% CI 0.762-0.932) and validation cohort (AUC = 0.817, 95% CI 0.625-1.000). RAISm outperformed single modality signatures and other combinations of signatures in terms of discrimination and clinical net benefits.

CONCLUSION

We pioneered combining preoperative CT-based radiomics with STAS to predict stage I LUAD recurrence postoperatively and confirmed the superior effect of the model in validation cohorts, showing its potential to assist in postoperative treatment strategies.

Importance of CT Scan in Predicting the Outcomes of Tibial Plateau Fractures: A Retrospective Study of 216 Patients over 10 Years' Time

BACKGROUND

The primary aim of this retrospective study was to assess the postoperative clinical, functional, and radiographic outcomes of patients with closed tibial plateau fractures (TPFs) surgically treated with proximal tibial locking compression plate (LCP) system with a focus on the use of preoperative CT scan.

METHODS

Two hundred and sixteen patients with TPFs who underwent surgical treatment in our department between January 2010 and December 2019 were enrolled in this study. Ninety-five patients of 216 (44.0%) had preoperative CT examination in addition to plain radiographs to better evaluate the pattern of fracture and displacement of fragments. Clinical and functional outcomes were assessed using VAS, SF-36, Knee Society Score (KSS) and WOMAC score. Radiographic outcomes were evaluated according to the Kellgreen- Lawrence classification of the pre- and postoperative grades of valgus knee, articular displacement and gonarthrosis.

RESULTS

Patients with preoperative CT showed better clinical results than the X-ray group for the VAS, KSS, WOMAC and SF-36 score. Moreover, we found that the X-ray group had worse results than the CT group in the rate of varus-valgus alignment and step-off worsening, while the posterior tibial slope showed no significant changes between the two groups at the final follow-up. Finally, the group of patients who received preoperative CT scans displayed a better immediate postoperative reduction and less long-term arthritis.

CONCLUSION

CT has proved to be a good examination in preoperative planning of TPFs: it can influence postoperative results thanks to an improvement in the surgical approach, a better evaluation of the morphology of fracture lines and the involvement of the Luo's three columns in axial CT scans.