An Interobserver Agreement Study with a New Classification for Rib Fractures

Interobserver agreement for the Chest Wall Injury Society taxonomy of rib fractures using computed tomography images

BACKGROUND

In 2020, a universal nomenclature for rib fractures was proposed by the international Chest Wall Injury Society taxonomy collaboration. The purpose of this study is to validate this taxonomy. We hypothesized that there would be at least moderate agreement, regardless of the observers' background.

METHODS

An international group of independent observers evaluated axial, coronal, and sagittal computed tomography images on an online platform from 11 rib fractures for location (anterior, lateral, or posterior), type (simple, wedge, or complex), and displacement (undisplaced, offset, or displaced) of rib fractures. The multirater κ and Gwet's first agreement coefficient (AC1) were calculated to estimate agreement among the observers.

RESULTS

A total of 90 observers participated, with 76 complete responses (84%). Strong agreement was found for the classification of fracture location ( κ = 0.83 [95% confidence interval (CI) 0.69-0.97]; AC1, 0.84 [95% CI, 0.81-0.88]), moderate for fracture type ( κ = 0.46 [95% CI, 0.32-0.59]; AC1, 0.50 [95% CI, 0.45-0.55]), and fair for rib fracture displacement ( κ = 0.38 [95% CI, 0.21-0.54], AC1, 0.38 [95% CI, 0.34-0.42]).

CONCLUSION

Agreement on rib fracture location was strong and moderate for fracture type. Agreement on displacement was lower than expected. Evaluating strategies such as comprehensive education, additional imaging techniques, or further specification of the definitions will be needed to increase agreement on the classification of rib fracture type and displacement as defined by the Chest Wall Injury Society taxonomy.

LEVEL OF EVIDENCE

Diagnostic Test or Criteria; Level IV.

Detection of acute rib fractures on CT images with convolutional neural networks: effect of location and type of fracture and reader's experience

PURPOSE

The evaluation of all ribs on thin-slice CT images is time consuming and it can be difficult to accurately assess the location and type of rib fracture in an emergency. The aim of our study was to develop and validate a convolutional neural network (CNN) algorithm for the detection of acute rib fractures on thoracic CT images and to investigate the effect of the CNN algorithm on radiologists' performance.

METHODS

The dataset for development of a CNN consisted of 539 thoracic CT scans with 4906 acute rib fractures. A three-dimensional faster region-based CNN was trained and evaluated by using tenfold cross-validation. For an observer performance study to investigate the effect of CNN outputs on radiologists' performance, 30 thoracic CT scans (28 scans with 90 acute rib fractures and 2 without rib fractures) which were not included in the development dataset were used. Observer performance study involved eight radiologists who evaluated CT images first without and second with CNN outputs. The diagnostic performance was assessed by using figure of merit (FOM) values obtained from the jackknife free-response receiver operating characteristic (JAFROC) analysis.

RESULTS

When radiologists used the CNN output for detection of rib fractures, the mean FOM value significantly increased for all readers (0.759 to 0.819, P = 0.0004) and for displaced (0.925 to 0.995, P = 0.0028) and non-displaced fractures (0.678 to 0.732, P = 0.0116). At all rib levels except for the 1st and 12th ribs, the radiologists' true-positive fraction of the detection became significantly increased by using the CNN outputs.

CONCLUSION

The CNN specialized for the detection of acute rib fractures on CT images can improve the radiologists' diagnostic performance regardless of the type of fractures and reader's experience. Further studies are needed to clarify the usefulness of the CNN for the detection of acute rib fractures on CT images in actual clinical practice.

Magnetic Resonance Imaging has Better Accuracy in Detecting New-Onset Rib Fractures as Compared to Computed Tomography

Background

The aim of this study was to explore the magnetic resonance imaging (MRI) manifestations of new-onset rib fractures and determine the utility of MRI through a comparative study of MRI and computed tomography (CT).

Material/Methods

Twenty-one patients with mild chest trauma who sought medical care from February 2019 to June 2020 were included in this study. The patients were subjected to CT and MRI scanning within 2 weeks after the trauma, and CT rescanning was scheduled 4–8 weeks later to classify rib fractures and determine the diagnostic accuracy of MRI and CT for new-onset rib fractures.

Results

Seventy-seven rib fractures were confirmed by CT rescanning, of which 72 (93.51%) were type I fractures and 5 (6.49%) were type II. MRI identified 76 fractures, of which 3 were false positive, with the diagnostic accuracy rate of 91.25% and sensitivity rate of 94.81%. Among them, type I fractures (n=71, 3 were false positive) showed the MRI “sandwich” sign (heterogeneous high-signal shadow within bone marrow of the inner layer, low-signal bony cortex of the middle layer, and high-signal subperiosteal effusion of the outer layer) in T2-weighted fat-suppressed sequences; type II fractures (n=5) displayed intramedullary high-signal intensities and no subperiosteal effusion. Forty-four fractures (all type I) were discovered in the initial CT examination, and the corresponding diagnostic accuracy rate and sensitivity rate were 57.14%, which were lower than that of MRI.

Conclusions

MRI is highly sensitive for new-onset rib fractures, especially type I, so it is a preferred method for patients with mild chest trauma.

Improving rib fracture detection accuracy and reading efficiency with deep learning-based detection software: a clinical evaluation

OBJECTIVES

To investigate the impact of deep learning (DL) on radiologists' detection accuracy and reading efficiency of rib fractures on CT.

METHODS

Blunt chest trauma patients (n = 198) undergoing thin-slice CT were enrolled. Images were read by two radiologists (R1, R2) in three sessions: S1, unassisted reading; S2, assisted by DL as the concurrent reader; S3, DL as the second reader. The fractures detected by the readers and total reading time were documented. The reference standard for rib fractures was established by an expert panel. The sensitivity and false-positives per scan were calculated and compared among S1, S2, and S3.

RESULTS

The reference standard identified 865 fractures on 713 ribs (102 patients) The sensitivity of S1, S2, and S3 was 82.8, 88.9, and 88.7% for R1, and 83.9, 88.7, and 88.8% for R2, respectively. The sensitivity of S2 and S3 was significantly higher compared to S1 for both readers (all p < 0.05). The sensitivity between S2 and S3 did not differ significantly (both p > 0.9). The false-positive per scan had no difference between sessions for R1 (p = 0.24) but was lower for S2 and S3 than S1 for R2 (both p < 0.05). Reading time decreased by 36% (R1) and 34% (R2) in S2 compared to S1.

CONCLUSIONS

Using DL as a concurrent reader can improve the detection accuracy and reading efficiency for rib fracture.

ADVANCES IN KNOWLEDGE

DL can be integrated into the radiology workflow to improve the accuracy and reading efficiency of CT rib fracture detection.

Clinical efficacy of surgical versus conservative treatment for multiple rib fractures: A meta-analysis of randomized controlled trials

BACKGROUND

There are still controversies between surgical treatment and conservative treatment for multiple rib fractures (MRFs). No consensus has been reached concerning the indications and timing of surgery. In this meta-analysis, we aimed to determine the optimal treatment for MRFs.

METHODS

Six databases (PubMed, Medline, Embase, Cochrane, Cnki, Wanfang Database) were retrieved for all eligible randomized controlled trials (RCTs) published before January 2020. MRFs were treated either with operative reduction and internal fixation or conservative treatment. The pertinent data were retrieved. The quality of RCTs was evaluated by the modified Jadad rating scale and meta-analysis was performed using RevMan 5.3 software.

RESULTS

Seven RCTs involving 538 MRFs patients (260 were treated surgically vs. 278 conservatively) were included in this meta-analysis. Compared with conservative treatment, surgical treatment resulted in shorter length of hospital stay (WMD -8.48; 95% CI -11.34 to -5.63; P < 0.001), length of ICU stay (WMD -5.72; 95% CI -7.31 to -4.13; P < 0.001) and duration of mechanical ventilation (WMD -4.93; 95% CI -8.79 to -1.07; P = 0.01), with a lower risk of complications including pneumonia (RR 0.40; 95% CI 0.30 to 0.53; P < 0.001) and chest wall deformity (RR 0.07; 95% CI 0.03 to 0.14; P < 0.001). The sensitivity analysis carried out by excluding one study with significant heterogeneity showed that the rate of tracheostomy was lower in the surgical group than in the conservative group (RR 0.44; 95% CI 0.28 to 0.71; P = 0.0008).

CONCLUSIONS

For patients with MRFs, surgical treatment resulted in faster recovery, a lower risk of complications and better prognosis than conservative treatment.

Rib fractures after blunt thoracic trauma in patients with normal versus diminished bone mineral density: a retrospective cohort study

This study aimed to evaluate rib fracture rate as well as rib fracture characteristics after thoracic trauma in patients with normal versus diminished bone mineral density (BMD). A retrospective cohort study of persons aged 50 years or older presenting to the Emergency Department after sustaining blunt thoracic trauma between July 1, 2014, and December 31, 2017, was performed. Patient and trauma characteristics and DXA scan results were collected. Rib fracture rate and characteristics were evaluated on a radiograph and/or CT scan of the thorax. In total, 119 patients were included for analysis. Fifty-eight of them (49%) had a diminished BMD. In the remaining 61, the BMD was normal. The diminished BMD group experienced rib fractures more often than the normal BMD group (n = 43 (74%) versus n = 31 (51%); p = 0.014). Patients with diminished BMD suffered low-energy trauma more frequently than the normal BMD group (21 (36%) versus 11 patients (15%), respectively (p = 0.011)). Rib fracture characteristics such as the median number of rib fractures, concomitant intrathoracic injury rate, and rib fracture type distribution were not different between the groups. The rate of rib fractures after blunt thoracic trauma was significantly higher in patients with diminished BMD than in patients with a normal BMD. Differences in number and location of rib fractures between groups could not be proven. When assessing patients aged 50 years or older presenting to the hospital after substantial blunt thoracic trauma, the presence of diminished BMD should be taken into account and the presence of rib fractures should be investigated with appropriate diagnostic procedures. Diminished bone mineral density (i.e., osteopenia or osteoporosis) is associated with increased fracture risk. This study evaluated if diminished BMD increases the rib fracture risk. Patients with diminished BMD have a higher risk of sustaining rib fractures after substantial blunt thoracic trauma, which implicates a lower threshold for CT imaging of the chest.