Lung cancer screening by nodule volume in Lung-RADS v1.1: negative baseline CT yields potential for increased screening interval

Objectives

The 2019 Lung CT Screening Reporting & Data System version 1.1 (Lung-RADS v1.1) introduced volumetric categories for nodule management. The aims of this study were to report the distribution of Lung-RADS v1.1 volumetric categories and to analyse lung cancer (LC) outcomes within 3 years for exploring personalized algorithm for lung cancer screening (LCS).

Methods

Subjects from the Multicentric Italian Lung Detection (MILD) trial were retrospectively selected by National Lung Screening Trial (NLST) criteria. Baseline characteristics included selected pre-test metrics and nodule characterization according to the volume-based categories of Lung-RADS v1.1. Nodule volume was obtained by segmentation with dedicated semi-automatic software. Primary outcome was diagnosis of LC, tested by univariate and multivariable models. Secondary outcome was stage of LC. Increased interval algorithms were simulated for testing rate of delayed diagnosis (RDD) and reduction of low-dose computed tomography (LDCT) burden.

Results

In 1248 NLST-eligible subjects, LC frequency was 1.2% at 1 year, 1.8% at 2 years and 2.6% at 3 years. Nodule volume in Lung-RADS v1.1 was a strong predictor of LC: positive LDCT showed an odds ratio (OR) of 75.60 at 1 year (p < 0.0001), and indeterminate LDCT showed an OR of 9.16 at 2 years (p = 0.0068) and an OR of 6.35 at 3 years (p = 0.0042). In the first 2 years after negative LDCT, 100% of resected LC was stage I. The simulations of low-frequency screening showed a RDD of 13.6–21.9% and a potential reduction of LDCT burden of 25.5–41%.

Conclusions

Nodule volume by semi-automatic software allowed stratification of LC risk across Lung-RADS v1.1 categories. Personalized screening algorithm by increased interval seems feasible in 80% of NLST eligible.

Key Points

• Using semi-automatic segmentation of nodule volume, Lung-RADS v1.1 selected 10.8% of subjects with positive CT and 96.87 relative risk of lung cancer at 1 year, compared to negative CT.

• Negative low-dose CT by Lung-RADS v1.1 was found in 80.6% of NLST eligible and yielded 40 times lower relative risk of lung cancer at 2 years, compared to positive low-dose CT; annual screening could be preference sensitive in this group.

• Semi-automatic segmentation of nodule volume and increased screening interval by volumetric Lung-RADS v1.1 could retrospectively suggest a 25.5–41% reduction of LDCT burden, at the cost of 13.6–21.9% rate of delayed diagnosis.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-07275-w) contains supplementary material, which is available to authorized users.

[Standardization and modeling of surgical processes]

BACKGROUND

Due to the technological developments around the operating room, surgery in the twenty-first century is undergoing a paradigm shift.

OBJECTIVE

Which technologies have already been integrated into the surgical routine? How can a favorable cost-benefit balance be achieved by the implementation of new software-based assistance systems?

METHODS

This article presents the state of the art technology as exemplified by a semi-automated operation system for otorhinolaryngology surgery. The main focus is on systems for implementation of digital handbooks and navigational functions in situ.

RESULTS

On the basis of continuous development in digital imaging, decisions may by facilitated by individual patient models thus allowing procedures to be optimized. The ongoing digitization and linking of all relevant information enable a high level of standardization in terms of operating procedures. This may be used by assistance systems as a basis for complete documentation and high process reliability.

CONCLUSION

Automation of processes in the operating room results in an increase in quality, precision and standardization so that the effectiveness and efficiency of treatment can be improved; however, care must be taken that detrimental consequences, such as loss of skills and placing too much faith in technology must be avoided by adapted training concepts.

[Osteoporosis detection using cone-beam computed tomography]

BACKGROUND

Osteoporosis is still underdiagnosed in Germany.

OBJECTIVES

Is it possible to detect osteoporosis on the basis of a cone-beam computed tomography image of the mandible and several measuring methods?

MATERIALS AND METHODS

Sixteen cone-beam computed tomography (CBCT) images from patients of the dental clinic at the University of Ulm were reinvestigated. When the CBCT images were processed the subjects were at least 55 years old, and the mandible was completely mapped on the image. Furthermore, a dual-energy X‑ray absorptiometry scan or a CT bone mineral density test was required for every subject. The subjects were divided into an osteoporosis group and a control group. The computed tomography mental index (CTMI), the computed tomography mandibular index superior (CTI[S]) and the computed tomography mandibular index inferior (CTI[I]) were deployed for comparison of the groups. In the first instance a comparison of the osteoporosis and control groups was made for both male and female subjects. Subsequently, only the images of the female subjects were compared to each other.

RESULTS

A possibility for osteoporosis can be expressed at CTMI values located < 3.0 mm. As well for CTI(S) < 0.18 and CTI(I) < 0.23. There arises a 66.7 % sensitivity and 70 % specificity for the mixed subject group and an 80 % sensitivity and 57.1 % specificity for the female subject group for CTMI and CTI(S). Furthermore, there are 50.0 % sensitivity and 70 % specificity for the mixed subject group and 60.0 % sensitivity and 57.1 % specificity for the female subject group for the CTI(I).

CONCLUSION

CTMI, CTI(S) and CTI(I) are only suitable for osteoporosis detection to a limited extent.

First pass dual input volume CT-perfusion of lung lesions: The influence of the CT- value range settings on the perfusion values of benign and malignant entities

OBJECTIVE

To assess the influence of the lower threshold for segmentation of the volume of interest on the perfusion values in first-pass dual input volume CT-perfusion of lung lesions.

MATERIALS AND METHODS

Dual input maximum slope volume CT-perfusion was performed in 48 patients (mean age±standard deviation [SD], 68±10years; range, 46-87 years) who underwent subsequent CT-guided biopsy to evaluate a lung lesion. Using commercial perfusion software, a lower and upper threshold was set for determination of the CT-value range, which again determined the volume of interest for perfusion calculation. The pulmonary arterial flow (PAF), bronchial arterial flow (BAF), and perfusion index (PI; PAF/(PAF+BAF)) were calculated at following pre contrast CT value range settings: -80 to 150HU (setting 1), -200 to 150HU (setting 2), -300 to 150HU (setting 3), and -500 to 150HU (setting 4). Perfusion parameters were compared between benign (n, 15) and malignant (n, 33) lesions for each setting. Intraobserver- and interobserver reliability were calculated for setting 4.

RESULTS

Median PAF was significantly higher in malignant lesions than in benign lesions for all settings (53-96 versus 29-62mL/min/100mL, P<0.05). There was no significant difference in BAF between malignant and benign lesions. Median PAF of all lesions was significantly influenced by the CT value range setting (P<0.05), whereas the values increased from setting 1 to 4. Intraobserver analysis as well as interobserver analysis of PAF at setting 4 showed excellent reliability (Cronbach's alpha 0.98 and 0.95, respectively, P<0.01).

CONCLUSION

PAF derived from first-pass dual-input maximum slope volume CT perfusion is statistically significantly higher in malignant than in benign lesion, whereas the measurements are influenced by the lower threshold of the CT value range setting. This has to be considered when using cutoff values provided in the literature for differentiation between benign and malignant lung lesions.